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8 (eight) is the
natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called '' cardinal ...
following 7 and preceding 9.


In mathematics

8 is: * a
composite number A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor In mathematics, a divisor of an integer n, also called a factor ...
, its
proper divisor In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible or evenly divisible by ...
s being , , and . It is twice 4 or four times 2. * a
power of two A power of two is a number of the form where is an integer, that is, the result of exponentiation with number two as the base and integer  as the exponent. In a context where only integers are considered, is restricted to non-negat ...
, being 2 (two cubed), and is the first number of the form , being an integer greater than 1. * the first number which is neither
prime A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
nor
semiprime In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime ...
. * the base of the
octal The octal numeral system, or oct for short, is the radix, base-8 number system, and uses the Numerical digit, digits 0 to 7. This is to say that 10octal represents eight and 100octal represents sixty-four. However, English, like most languages, ...
number system, which is mostly used with
computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...
s. In octal, one digit represents three bits. In modern computers, a
byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...
is a grouping of eight bits, also called an
octet Octet may refer to: Music * Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble ** String octet, a piece of music written for eight string instruments *** Octet (Mendelssohn), 1825 com ...
. * a Fibonacci number, being plus . The next Fibonacci number is . 8 is the only positive Fibonacci number, aside from 1, that is a perfect cube. * the only nonzero perfect power that is one less than another perfect power, by
Mihăilescu's Theorem Catalan's conjecture (or Mihăilescu's theorem) is a theorem in number theory that was conjectured by the mathematician Eugène Charles Catalan in 1844 and proven in 2002 by Preda Mihăilescu at Paderborn University. The integers 23 and 32 are ...
. * the order of the smallest non-abelian group all of whose subgroups are normal. * the dimension of the
octonion In mathematics, the octonions are a normed division algebra over the real numbers, a kind of hypercomplex number system. The octonions are usually represented by the capital letter O, using boldface or blackboard bold \mathbb O. Octonions hav ...
s and is the highest possible dimension of a normed division algebra. * the first number to be the aliquot sum of two numbers other than itself; the discrete biprime , and the square number . A number is divisible by 8 if its last three digits, when written in
decimal The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral ...
, are also divisible by 8, or its last three digits are 0 when written in binary. A
polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed '' polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two ...
with eight sides is an
octagon In geometry, an octagon (from the Greek ὀκτάγωνον ''oktágōnon'', "eight angles") is an eight-sided polygon or 8-gon. A '' regular octagon'' has Schläfli symbol and can also be constructed as a quasiregular truncated square, t, w ...
. The sides and span of a regular octagon, or truncated square, are in silver ratio, and its circumscribing square has a side and diagonal length ratio of ; with both the silver ratio and the square root of two intimately interconnected through Pell numbers, where in particular the quotient of successive Pell numbers generates rational approximations for coordinates of a regular octagon. With a
central angle A central angle is an angle whose apex (vertex) is the center O of a circle and whose legs (sides) are radii intersecting the circle in two distinct points A and B. Central angles are subtended by an arc between those two points, and the arc le ...
of 45 degrees and an internal angle of 135 degrees, regular octagons are able to
tessellate A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called ''tiles'', with no overlaps and no gaps. In mathematics, tessellation can be generalized to higher dimensions and a variety of ...
two-dimensional space alongside squares in the truncated square tiling, as well as fill a plane-vertex with a regular
triangle A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, any three points, when non- colline ...
and a regular
icositetragon In geometry, an icositetragon (or icosikaitetragon) or 24-gon is a twenty-four-sided polygon. The sum of any icositetragon's interior angles is 3960 degrees. Regular icositetragon The '' regular icositetragon'' is represented by Schläfli symbol ...
. The
Ammann–Beenker tiling In geometry, an Ammann–Beenker tiling is a nonperiodic tiling which can be generated either by an aperiodic set of prototiles as done by Robert Ammann in the 1970s, or by the cut-and-project method as done independently by F. P. M. Beenker. ...
is a nonperiodic tesselation of prototiles that feature prominent octagonal ''silver'' eightfold symmetry, and is the two-dimensional orthogonal projection of the
8-8 duoprism In geometry of 4 dimensions or higher, a double prism or duoprism is a polytope resulting from the Cartesian product of two polytopes, each of two dimensions or higher. The Cartesian product of an -polytope and an -polytope is an -polytope, wher ...
. In number theory, figurate numbers representing octagons are called octagonal numbers. A
cube In geometry, a cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. Viewed from a corner it is a hexagon and its net is usually depicted as a cross. The cube is the only ...
is a regular polyhedron with eight vertices that also forms the cubic honeycomb, the only regular honeycomb in three-dimensional space. Through various truncation operations, the cubic honeycomb generates eight other convex uniform honeycombs under the group _3. The
octahedron In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...
, with eight
equilateral triangle In geometry, an equilateral triangle is a triangle in which all three sides have the same length. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each oth ...
s as faces, is the
dual polyhedron In geometry, every polyhedron is associated with a second dual structure, where the vertices of one correspond to the faces of the other, and the edges between pairs of vertices of one correspond to the edges between pairs of faces of the oth ...
to the cube and one of eight convex deltahedra. The stella octangula, or ''eight-pointed star'', is the only
stellation In geometry, stellation is the process of extending a polygon in two dimensions, polyhedron in three dimensions, or, in general, a polytope in ''n'' dimensions to form a new figure. Starting with an original figure, the process extends specif ...
with octahedral symmetry. It has eight triangular faces alongside eight vertices that form a cubic
faceting Stella octangula as a faceting of the cube In geometry, faceting (also spelled facetting) is the process of removing parts of a polygon, polyhedron or polytope, without creating any new vertices. New edges of a faceted polyhedron may be ...
, composed of two self-dual
tetrahedra In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all th ...
that makes it the simplest of five regular compound polyhedra. The cuboctahedron, on the other hand, is a rectified cube or rectified octahedron, and one of only two convex
quasiregular polyhedra In geometry, a quasiregular polyhedron is a uniform polyhedron that has exactly two kinds of regular faces, which alternate around each vertex. They are vertex-transitive and edge-transitive, hence a step closer to regular polyhedra than the sem ...
. It contains eight equilateral triangular faces alongside six squares, whose first
stellation In geometry, stellation is the process of extending a polygon in two dimensions, polyhedron in three dimensions, or, in general, a polytope in ''n'' dimensions to form a new figure. Starting with an original figure, the process extends specif ...
is the cube-octahedron compound. The hexagonal prism, which classifies as an irregular octahedron that is a parallelohedron, like the cube, is able to
tessellate A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called ''tiles'', with no overlaps and no gaps. In mathematics, tessellation can be generalized to higher dimensions and a variety of ...
space as a three-dimensional analogue of the
hexagon In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...
. The gyrobifastigium, with four square faces and four triangular faces, is the only
Johnson solid In geometry, a Johnson solid is a strictly convex polyhedron each face of which is a regular polygon. There is no requirement that each face must be the same polygon, or that the same polygons join around each vertex. An example of a Johnso ...
that is able to tessellate space, while the truncated octahedron, also a parallelohedron, is the permutohedron of order four, with eight hexagonal faces alongside six squares that is likewise the only
Archimedean solid In geometry, an Archimedean solid is one of the 13 solids first enumerated by Archimedes. They are the convex uniform polyhedra composed of regular polygons meeting in identical vertices, excluding the five Platonic solids (which are compose ...
that can generate a honeycomb on its own.
Vertex-transitive In geometry, a polytope (e.g. a polygon or polyhedron) or a tiling is isogonal or vertex-transitive if all its vertices are equivalent under the symmetries of the figure. This implies that each vertex is surrounded by the same kinds of fa ...
semiregular polytopes whose facets are ''finite'' exist up through the 8th dimension. In the
third dimension Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...
, they include the Archimedean solids and the infinite family of uniform
prisms Prism usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentar ...
and antiprisms, while in the fourth dimension, only the rectified 5-cell, the rectified 600-cell, and the
snub 24-cell In geometry, the snub 24-cell or snub disicositetrachoron is a convex uniform 4-polytope composed of 120 regular tetrahedral and 24 icosahedral cells. Five tetrahedra and three icosahedra meet at each vertex. In total it has 480 triangular face ...
are semiregular polytopes. For dimensions
five 5 is a number, numeral, and glyph. 5, five or number 5 may also refer to: * AD 5, the fifth year of the AD era * 5 BC, the fifth year before the AD era Literature * ''5'' (visual novel), a 2008 visual novel by Ram * ''5'' (comics), an awa ...
through eight, the
demipenteract In five-dimensional geometry, a demipenteract or 5-demicube is a semiregular 5-polytope, constructed from a ''5-hypercube'' ( penteract) with alternated vertices removed. It was discovered by Thorold Gosset. Since it was the only semiregular ...
and the k21 polytopes 221, 321, and 421 are the only semiregular ( Gosset) polytopes. Collectively, the k21 family of polytopes contains eight figures that are rooted in the
triangular prism In geometry, a triangular prism is a three-sided prism; it is a polyhedron made of a triangular base, a translated copy, and 3 faces joining corresponding sides. A right triangular prism has rectangular sides, otherwise it is ''oblique''. A ...
, which is the simplest semiregular polytope that is made of three cubes and two equilateral triangles. It also includes one of only three semiregular Euclidean honeycombs: the affine 521 honeycomb that represents the arrangement of vertices of the eight-dimensional \mathrm E_ lattice, and made of 421 facets. The culminating figure is the ninth-dimensional 621 honeycomb, which is the only affine semiregular paracompact hyperbolic honeycomb with infinite facets and
vertex figure In geometry, a vertex figure, broadly speaking, is the figure exposed when a corner of a polyhedron or polytope is sliced off. Definitions Take some corner or vertex of a polyhedron. Mark a point somewhere along each connected edge. Draw line ...
s in the k21 family. There are no other finite semiregular polytopes or honeycombs in dimensions ''n'' > 8. Sphenic numbers always have exactly eight divisors. The number 8 is involved with a number of interesting mathematical phenomena related to the notion of Bott periodicity. If O(\infty) is the direct limit of the inclusions of real orthogonal groups O(1)\hookrightarrow O(2)\hookrightarrow\ldots\hookrightarrow O(k)\hookrightarrow\ldots, the following holds: :\pi_(O(\infty))\cong\pi_(O(\infty)). Clifford algebras also display a periodicity of 8. For example, the algebra ''Cl''(''p'' + 8,''q'') is isomorphic to the algebra of 16 by 16 matrices with entries in ''Cl''(''p'',''q''). We also see a period of 8 in the K-theory of spheres and in the
representation theory Representation theory is a branch of mathematics that studies abstract algebraic structures by ''representing'' their elements as linear transformations of vector spaces, and studies modules over these abstract algebraic structures. In essen ...
of the rotation groups, the latter giving rise to the 8 by 8
spinor In geometry and physics, spinors are elements of a complex vector space that can be associated with Euclidean space. Like geometric vectors and more general tensors, spinors transform linearly when the Euclidean space is subjected to a sligh ...
ial chessboard. All of these properties are closely related to the properties of the
octonion In mathematics, the octonions are a normed division algebra over the real numbers, a kind of hypercomplex number system. The octonions are usually represented by the capital letter O, using boldface or blackboard bold \mathbb O. Octonions hav ...
s. The
spin group In mathematics the spin group Spin(''n'') page 15 is the double cover of the special orthogonal group , such that there exists a short exact sequence of Lie groups (when ) :1 \to \mathrm_2 \to \operatorname(n) \to \operatorname(n) \to 1. As a ...
Spin(8) is the unique such group that exhibits the phenomenon of triality. The lowest-dimensional even unimodular lattice is the 8-dimensional \mathrm E_ lattice. Even positive definite unimodular lattices exist only in dimensions divisible by 8. A figure 8 is the common name of a
geometric Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...
shape A shape or figure is a graphical representation of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type. A plane shape or plane figure is constrained to lie ...
, often used in the context of sports, such as skating. Figure-eight turns of a rope or cable around a cleat, pin, or bitt are used to belay something.


List of basic calculations


Etymology

English ''eight'', from Old English ''eahta, æhta'',
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic br ...
''*ahto'' is a direct continuation of
Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo ...
'' *oḱtṓ(w)-'', and as such cognate with Greek and Latin ''octo-'', both of which stems are reflected by the English prefix oct(o)-, as in the ordinal adjective ''octaval'' or ''octavary'', the distributive adjective is '' octonary''. The adjective ''octuple'' (Latin ''octu-plus'') may also be used as a noun, meaning "a set of eight items"; the diminutive '' octuplet'' is mostly used to refer to eight siblings delivered in one birth. The Semitic numeral is based on a root ''*θmn-'', whence Akkadian ''smn-'', Arabic ''ṯmn-'', Hebrew ''šmn-'' etc. The
Chinese numeral Chinese numerals are words and characters used to denote numbers in Chinese. Today, speakers of Chinese use three written numeral systems: the system of Arabic numerals used worldwide, and two indigenous systems. The more familiar indigenous ...
, written ( Mandarin: ''bā'';
Cantonese Cantonese ( zh, t=廣東話, s=广东话, first=t, cy=Gwóngdūng wá) is a language within the Chinese (Sinitic) branch of the Sino-Tibetan languages originating from the city of Guangzhou (historically known as Canton) and its surrounding a ...
: ''baat''), is from
Old Chinese Old Chinese, also called Archaic Chinese in older works, is the oldest attested stage of Chinese, and the ancestor of all modern varieties of Chinese. The earliest examples of Chinese are divinatory inscriptions on oracle bones from around 12 ...
''*priāt-'', ultimately from Sino-Tibetan ''b-r-gyat'' or ''b-g-ryat'' which also yielded Tibetan '' brgyat''. It has been argued that, as the
cardinal number In mathematics, cardinal numbers, or cardinals for short, are a generalization of the natural numbers used to measure the cardinality (size) of sets. The cardinality of a finite set is a natural number: the number of elements in the set. ...
is the highest number of items that can universally be cognitively processed as a single set, the etymology of the numeral ''eight'' might be the first to be considered composite, either as "twice four" or as "two short of ten", or similar. The Turkic words for "eight" are from a Proto-Turkic stem ''*sekiz'', which has been suggested as originating as a negation of ''eki'' "two", as in "without two fingers" (i.e., "two short of ten; two fingers are not being held up"); this same principle is found in Finnic '' *kakte-ksa'', which conveys a meaning of "two before (ten)". The Proto-Indo-European reconstruction '' *oḱtṓ(w)-'' itself has been argued as representing an old dual, which would correspond to an original meaning of "twice four". Proponents of this "quaternary hypothesis" adduce the numeral ', which might be built on the stem ''new-'', meaning "new" (indicating the beginning of a "new set of numerals" after having counted to eight).


Evolution of the Arabic digit

The modern digit 8, like all modern
Arabic numerals Arabic numerals are the ten numerical digits: , , , , , , , , and . They are the most commonly used symbols to write decimal numbers. They are also used for writing numbers in other systems such as octal, and for writing identifiers such a ...
other than zero, originates with the
Brahmi numerals The Brahmi numerals are a numeral system attested from the 3rd century BCE (somewhat later in the case of most of the tens). They are a non positional decimal system. They are the direct graphic ancestors of the modern Hindu–Arabic numeral ...
. The Brahmi digit for ''eight'' by the 1st century was written in one stroke as a curve └┐ looking like an uppercase H with the bottom half of the left line and the upper half of the right line removed. However, the digit for eight used in India in the early centuries of the Common Era developed considerable graphic variation, and in some cases took the shape of a single wedge, which was adopted into the Perso-Arabic tradition as ٨ (and also gave rise to the later Devanagari form ); the alternative curved glyph also existed as a variant in Perso-Arabic tradition, where it came to look similar to our digit 5. The digits as used in
Al-Andalus Al-Andalus translit. ; an, al-Andalus; ast, al-Ándalus; eu, al-Andalus; ber, ⴰⵏⴷⴰⵍⵓⵙ, label= Berber, translit=Andalus; ca, al-Àndalus; gl, al-Andalus; oc, Al Andalús; pt, al-Ândalus; es, al-Ándalus () was the M ...
by the 10th century were a distinctive western variant of the glyphs used in the Arabic-speaking world, known as ''ghubār'' numerals (''ghubār'' translating to " sand table"). In these digits, the line of the ''5''-like glyph used in Indian manuscripts for eight came to be formed in ghubār as a closed loop, which was the ''8''-shape that became adopted into European use in the 10th century. Just as in most modern
typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are thousands o ...
s, in typefaces with
text figures Text figures (also known as non-lining, lowercase, old style, ranging, hanging, medieval, billing, or antique figures or numerals) are numerals designed with varying heights in a fashion that resembles a typical line of running text, hence the ...
the character for the digit 8 usually has an ascender, as, for example, in . The infinity symbol ∞, described as a "sideways figure eight", is unrelated to the digit 8 in origin; it is first used (in the mathematical meaning "infinity") in the 17th century, and it may be derived from the
Roman numeral Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, ea ...
for "one thousand" CIƆ, or alternatively from the final Greek letter, ω.


In science


Physics

* In nuclear physics, the second magic number. * In
particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
, the eightfold way is used to classify sub-atomic particles. * In
statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic b ...
, the eight-vertex model has 8 possible configurations of arrows at each vertex.


Astronomy

* Messier object M8, a magnitude 5.0
nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...
in the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellation ...
of Sagittarius. * The
New General Catalogue The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and ...
br>object
NGC 8, a double star in the constellation
Pegasus Pegasus ( grc-gre, Πήγασος, Pḗgasos; la, Pegasus, Pegasos) is one of the best known creatures in Greek mythology. He is a winged divine stallion usually depicted as pure white in color. He was sired by Poseidon, in his role as hor ...
. * Since the demotion of
Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...
to a
dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets but still a world in its own right. The prototypical dwarf planet is Pluto. The interest of dwarf planets to ...
on 24 August 2006, in our
Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
, eight of the bodies orbiting the Sun are considered to be
planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s.


Chemistry

* The
atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of ever ...
of
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
. * The most stable allotrope of a
sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...
molecule is made of eight sulfur atoms arranged in a rhombic form. * The maximum number of electrons that can occupy a valence shell. * The red pigment
lycopene Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene (from the neo-Latin '' Lycopersicum'', the tomato species) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables. Occu ...
consists of eight
isoprene Isoprene, or 2-methyl-1,3-butadiene, is a common volatile organic compound with the formula CH2=C(CH3)−CH=CH2. In its pure form it is a colorless volatile liquid. Isoprene is an unsaturated hydrocarbon. It is produced by many plants and animals ...
units.


Geology

* A
disphenoid In geometry, a disphenoid () is a tetrahedron whose four faces are congruent acute-angled triangles. It can also be described as a tetrahedron in which every two edges that are opposite each other have equal lengths. Other names for the same ...
crystal is bounded by eight scalene triangles arranged in pairs. A ditetragonal prism in the
tetragonal crystal system In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a squar ...
has eight similar faces whose alternate interfacial angles only are equal.


Biology

* All
spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s, and more generally all
arachnid Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegar ...
s, have eight legs. Orb-weaver spiders of the cosmopolitan family Areneidae have eight similar eyes. * The
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, ...
and its cephalopod relatives in genus ''Argonauta'' have eight arms (tentacles). * Compound coelenterates of the subclass or order Alcyonaria have polyps with eight-branched tentacles and eight septa. * Sea anemones of genus '' Edwardsia'' have eight mesenteries. * Animals of phylum
Ctenophora Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and ...
swim by means of eight meridional bands of transverse ciliated plates, each plate representing a row of large modified cilia. * The eight-spotted forester (genus ''Alypia'', family
Zygaenidae The Zygaenidae moths are a family of Lepidoptera. The majority of zygaenids are tropical, but they are nevertheless quite well represented in temperate regions. Some of the 1000 or so species are commonly known as burnet or forester moths, oft ...
) is a diurnal moth having black wings with brilliant white spots. * The
ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...
in fungi of the class
Ascomycetes Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...
, following nuclear fusion, bears within it typically eight ascospores. * Herbs of genus ''
Coreopsis ''Coreopsis'' () is a genus of flowering plants in the family Asteraceae. Common names include calliopsis and tickseed, a name shared with various other plants. Description These plants range from in height. The flowers are usually yellow wi ...
'' (tickseed) have showy flower heads with involucral bracts in two distinct series of eight each. * In human adult dentition there are eight teeth in each quadrant. The eighth tooth is the so-called
wisdom tooth A third molar, commonly called wisdom tooth, is one of the three molars per quadrant of the human dentition. It is the most posterior of the three. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs betw ...
. * There are eight cervical nerves on each side in man and most mammals.


Psychology

* There are eight Jungian cognitive functions, according to the MBTI models by John Beebe and Linda Berens. *
Timothy Leary Timothy Francis Leary (October 22, 1920 – May 31, 1996) was an American psychologist and author known for his strong advocacy of psychedelic drugs. Evaluations of Leary are polarized, ranging from bold oracle to publicity hound. He was "a her ...
identified a hierarchy of eight levels of consciousness.


In technology

* A
byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...
is eight bits. * Many (mostly historic) computer architectures are eight-bit, among them the
Nintendo Entertainment System The Nintendo Entertainment System (NES) is an 8-bit third-generation home video game console produced by Nintendo. It was first released in Japan in 1983 as the commonly known as the The NES, a redesigned version, was released in America ...
. * Standard-8 and
Super-8 Super 8 mm film is a motion-picture film format released in 1965 by Eastman Kodak as an improvement over the older "Double" or "Regular" 8 mm home movie format. The film is nominally 8 mm wide, the same as older formatted 8& ...
are 8 mm
film formats A film format is a technical definition of a set of standard characteristics regarding image capture on photographic film for still images or film stock for filmmaking. It can also apply to projected film, either slides or movies. The primary ch ...
. * Video8, Hi8 and Digital8 are related
8 mm video format The 8mm video format refers informally to three related videocassette formats. These are the original Video8 ( analog recording) format and its improved successor Hi8 ( analog video and analog audio but with provision for digital audio), as wel ...
s. * On most phones, the 8 key is associated with the letters T, U, and V, but on the BlackBerry Pearl it is the key for B and N. * An eight may refer to an eight-cylinder engine or automobile. A
V8 engine A V8 engine is an eight-cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration. The first V8 engine was produced by the French Antoinette company in 1904, developed and u ...
is an
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...
with eight cylinders configured in two banks (rows) of four forming a "V" when seen from the end. * A figure-eight knot (so named for its configuration) is a kind of stopper knot. * The number eight written in parentheses is the code for the musical note in
Windows Live Messenger MSN Messenger (also known colloquially simply as "Messenger"), later rebranded as Windows Live Messenger, was a cross-platform instant-messaging client developed by Microsoft. It connected to the Microsoft Messenger service and, in later versio ...
. * In a
seven-segment display A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, bas ...
, when an 8 is illuminated, all the display bulbs are on.


In measurement

* The
SI prefix The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. ...
for 10008 is yotta (Y), and for its reciprocal, yocto (y). * In liquid measurement (
United States customary units United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English uni ...
), there are eight fluid ounces in a
cup A cup is an open-top used to hold hot or cold liquids for pouring or drinking; while mainly used for drinking, it also can be used to store solids for pouring (e.g., sugar, flour, grains, salt). Cups may be made of glass, metal, china, cl ...
, eight pints in a
gallon The gallon is a unit of volume in imperial units and United States customary units. Three different versions are in current use: *the imperial gallon (imp gal), defined as , which is or was used in the United Kingdom, Ireland, Canada, Aust ...
and eight tablespoonfuls in a
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...
. * There are eight
furlong A furlong is a measure of distance in imperial units and United States customary units equal to one eighth of a mile, equivalent to 660 feet, 220 yards, 40 rods, 10 chains or approximately 201 metres. It is now mostly confined to use in hor ...
s in a mile. * The clove, an old English unit of weight, was equal to eight pounds when measuring cheese. * An eight may be an article of clothing of the eighth
size Size in general is the magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions ( length, width, height, diameter, perimeter), area, or volume. Size can also be me ...
. * Force eight is the first
wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ...
strength attributed to a
gale A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface winds moving at a speed of between 34 and 47 knots (, or ).Beaufort scale The Beaufort scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort wind force scale. History The scale was devised in 1805 by the Irish hydrographer Francis Beaufort ...
when announced on a Shipping Forecast.


In culture


Currency

* Sailors and civilians alike from the 1500s onward referred to evenly divided parts of the Spanish dollar as "pieces of eight", or "bits".


Architecture

* Various types of buildings are usually eight-sided (octagonal), such as single-roomed
gazebo A gazebo is a pavilion structure, sometimes octagonal or turret-shaped, often built in a park, garden or spacious public area. Some are used on occasions as bandstands. Etymology The etymology given by Oxford Dictionaries is "Mid 18th c ...
s and multi-roomed
pagoda A pagoda is an Asian tiered tower with multiple eaves common to Nepal, India, China, Japan, Korea, Myanmar, Vietnam, and other parts of Asia. Most pagodas were built to have a religious function, most often Buddhist but sometimes Taoist, ...
s (descended from stupas; see religion section below). * Eight caulicoles rise out of the leafage in a
Corinthian capital The Corinthian order (Greek: Κορινθιακός ρυθμός, Latin: ''Ordo Corinthius'') is the last developed of the three principal classical orders of Ancient Greek architecture and Roman architecture. The other two are the Doric order w ...
, ending in leaves that support the
volutes A volute is a spiral, scroll-like ornament that forms the basis of the Ionic order, found in the capital of the Ionic column. It was later incorporated into Corinthian order and Composite column capitals. Four are normally to be found on an Ion ...
.


In religion, folk belief and divination


Hinduism

* Also known as Ashtha, Aṣṭa, or Ashta in
Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had Trans-cultural diffusion ...
, it is the number of wealth and abundance. * The goddess of wealth and prosperity,
Lakshmi Lakshmi (; , sometimes spelled Laxmi, ), also known as Shri (, ), is one of the principal goddesses in Hinduism. She is the goddess of wealth, fortune, power, beauty, fertility and prosperity, and associated with '' Maya'' ("Illusion"). A ...
, has eight forms known as Ashta Lakshmi and worshipped as:
"''Maha-lakshmi, Dhana-lakshmi, Dhanya-lakshmi, Gaja-lakshmi,
Santana-lakshmi, Veera-lakshmi, Vijaya-lakshmi and Vidhya-lakshmi''" *There are eight ''nidhi'', or seats of wealth, according to
Hinduism Hinduism () is an Indian religion or '' dharma'', a religious and universal order or way of life by which followers abide. As a religion, it is the world's third-largest, with over 1.2–1.35 billion followers, or 15–16% of the global p ...
. *There are eight guardians of the directions known as ''Astha-dikpalas''. *There are eight
Hindu Hindus (; ) are people who religiously adhere to Hinduism. Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pages 35–37 Historically, the term has also been used as a geographical, cultural, and later religious identifier for ...
monasteries established by the saint
Madhvacharya Madhvacharya (; ; CE 1199-1278 or CE 1238–1317), sometimes anglicised as Madhva Acharya, and also known as Purna Prajna () and Ānanda Tīrtha, was an Indian philosopher, theologian and the chief proponent of the '' Dvaita'' (dualism) sch ...
in
Udupi Udupi (alternate spelling Udipi; also known as Odipu) is a city in the Indian state of Karnataka. Udupi is situated about north of the educational, commercial and industrial hub of Mangalore and about west of state capital Bangalore by road. ...
,
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...
popularly known as the '' Ashta Mathas of Udupi''.


Buddhism

* The Dharmacakra, a
Buddhist Buddhism ( , ), also known as Buddha Dharma and Dharmavinaya (), is an Indian religion or philosophical tradition based on teachings attributed to the Buddha. It originated in northern India as a -movement in the 5th century BCE, and ...
symbol, has eight spokes. The Buddha's principal teaching—the
Four Noble Truths In Buddhism, the Four Noble Truths (Sanskrit: ; pi, cattāri ariyasaccāni; "The four Arya satyas") are "the truths of the Noble Ones", the truths or realities for the "spiritually worthy ones". Four Noble Truths: BUDDHIST PHILOSOPHY Encycl ...
—ramifies as the Noble Eightfold Path and the Buddha emphasizes the importance of the eight attainments or jhanas. * In Mahayana Buddhism, the branches of the Eightfold Path are embodied by the Eight Great Bodhisattvas: (Manjusri, Vajrapani, Avalokiteśvara, Maitreya, Ksitigarbha, Nivaranavishkambhi, Akasagarbha, and Samantabhadra (Bodhisattva), Samantabhadra). These are later (controversially) associated with the Eight Consciousnesses according to the Yogacara school of thought: consciousness in the five senses, thought-consciousness, self-consciousness, and unconsciousness-"consciousness" or "store-house consciousness" (alaya-vijñana). The "irreversible" state of enlightenment, at which point a Bodhisattva goes on "autopilot", is the Eight Ground or ''bhūmi''. In general, "eight" seems to be an auspicious number for Buddhists, e.g., the "eight auspicious symbols" (the jewel-encrusted parasol; the goldfish (always shown as a pair, e.g., the glyph of Pisces); the self-replenishing amphora; the white ''kamala'' lotus-flower; the white conch; the eternal (Celtic-style, infinitely looping) knot; the banner of imperial victory; the eight-spoked wheel that guides the ship of state, or that symbolizes the Buddha's teaching). Similarly,
Buddha's birthday Buddha's Birthday (also known as Buddha Jayanti, also known as his day of enlightenment – Buddha Purnima, Buddha Pournami) is a Buddhist festival that is celebrated in most of East Asia and South Asia commemorating the birth of the Prince ...
falls on the 8th day of the 4th month of the
Chinese calendar The traditional Chinese calendar (also known as the Agricultural Calendar ��曆; 农历; ''Nónglì''; 'farming calendar' Former Calendar ��曆; 旧历; ''Jiùlì'' Traditional Calendar ��曆; 老历; ''Lǎolì'', is a lunisolar calendar ...
.


Judaism

* The religious rite of
brit milah The ''brit milah'' ( he, בְּרִית מִילָה ''bərīṯ mīlā'', ; Ashkenazi pronunciation: , " covenant of circumcision"; Yiddish pronunciation: ''bris'' ) is the ceremony of circumcision in Judaism. According to the Book of Genes ...
(commonly known as
circumcision Circumcision is a procedure that removes the foreskin from the human penis. In the most common form of the operation, the foreskin is extended with forceps, then a circumcision device may be placed, after which the foreskin is excised. Top ...
) is held on a baby boy's eighth day of life. *
Hanukkah or English translation: 'Establishing' or 'Dedication' (of the Temple in Jerusalem) , nickname = , observedby = Jews , begins = 25 Kislev , ends = 2 Tevet or 3 Tevet , celebrations = Lighting candles each nig ...
is an eight-day Jewish holiday that starts on the 25th day of Kislev. *
Shemini Atzeret Shemini Atzeret (—"Eighth ay ofAssembly") is a Jewish holiday. It is celebrated on the 22nd day of the Hebrew month of Tishrei in the Land of Israel, and on the 22nd and 23rd outside the Land, usually coinciding with late September or earl ...
(
Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...
: "Eighth Day of Assembly") is a one-day Jewish holiday immediately following the seven-day holiday of
Sukkot or ("Booths, Tabernacles") , observedby = Jews, Samaritans, a few Protestant denominations, Messianic Jews, Semitic Neopagans , type = Jewish, Samaritan , begins = 15th day of Tishrei , ends = 21st day of Tis ...
.


Christianity

* The spiritual Eighth Day, because the number 7 refers to the days of the week (which repeat themselves). * The number of
Beatitudes The Beatitudes are sayings attributed to Jesus, and in particular eight blessings recounted by Jesus in the Sermon on the Mount in the Gospel of Matthew, and four in the Sermon on the Plain in the Gospel of Luke, followed by four woes which mir ...
. * 1 Peter 3:20 states that there were eight people on
Noah's Ark Noah's Ark ( he, תיבת נח; Biblical Hebrew: ''Tevat Noaḥ'')The word "ark" in modern English comes from Old English ''aerca'', meaning a chest or box. (See Cresswell 2010, p.22) The Hebrew word for the vessel, ''teva'', occurs twice in ...
. * The
Antichrist In Christian eschatology, the Antichrist refers to people prophesied by the Bible to oppose Jesus Christ and substitute themselves in Christ's place before the Second Coming. The term Antichrist (including one plural form)1 John ; . 2 John . ...
is the eighth king in the
Book of Revelation The Book of Revelation is the final book of the New Testament (and consequently the final book of the Christian Bible). Its title is derived from the first word of the Koine Greek text: , meaning "unveiling" or "revelation". The Book of ...
.


Islam

* In
Islam Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the ...
, eight is the number of
angel In various theistic religious traditions an angel is a supernatural spiritual being who serves God. Abrahamic religions often depict angels as benevolent celestial intermediaries between God (or Heaven) and humanity. Other roles ...
s carrying the
throne A throne is the seat of state of a potentate or dignitary, especially the seat occupied by a sovereign on state occasions; or the seat occupied by a pope or bishop on ceremonial occasions. "Throne" in an abstract sense can also refer to the mon ...
of
Allah Allah (; ar, الله, translit=Allāh, ) is the common Arabic word for God. In the English language, the word generally refers to God in Islam. The word is thought to be derived by contraction from '' al- ilāh'', which means "the god", a ...
in heaven. * The number of gates of heaven


Taoism

*
Ba Gua The bagua or pakua (八卦) are a set of eight symbols that originated in China, used in Taoist cosmology to represent the fundamental principles of reality, seen as a range of eight interrelated concepts. Each consists of three lines, each l ...
* Ba Xian * Ba Duan Jin


Other

* In
Wicca Wicca () is a modern Pagan religion. Scholars of religion categorise it as both a new religious movement and as part of the occultist stream of Western esotericism. It was developed in England during the first half of the 20th century and w ...
, there are eight Sabbats, festivals, seasons, or spokes in the
Wheel of the Year The Wheel of the Year is an annual cycle of seasonal festivals, observed by many modern pagans, consisting of the year's chief solar events (solstices and equinoxes) and the midpoints between them. While names for each festival vary among di ...
. * In Ancient Egyptian mythology, the Ogdoad represents the eight primordial deities of creation. * In Scientology there are eight dynamics of existence. * There is also the Ogdoad in
Gnosticism Gnosticism (from grc, γνωστικός, gnōstikós, , 'having knowledge') is a collection of religious ideas and systems which coalesced in the late 1st century AD among Jewish and early Christian sects. These various groups emphasized pe ...
.


As a lucky number

* The number eight is considered to be a lucky number in Chinese and other Asian cultures. Eight (;
accounting Accounting, also known as accountancy, is the measurement, processing, and communication of financial and non financial information about economic entities such as businesses and corporations. Accounting, which has been called the "languag ...
;
pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally written in Chinese fo ...
''bā'') is considered a lucky number in Chinese culture because it sounds like the word meaning to generate wealth (;
Pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally written in Chinese fo ...
: ''fā''). Property with the number 8 may be valued greatly by Chinese. For example, a Hong Kong number plate with the number 8 was sold for $640,000. The opening ceremony of the Summer Olympics in Beijing started at 8 seconds and 8 minutes past 8 pm (local time) on 8 August 2008. * In Pythagorean
numerology Numerology (also known as arithmancy) is the belief in an occult, divine or mystical relationship between a number and one or more coinciding events. It is also the study of the numerical value, via an alphanumeric system, of the letters in ...
(a
pseudoscience Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claim ...
) the number 8 represents victory, prosperity and overcoming. * is also considered a lucky number in
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...
, but the reason is different from that in Chinese culture. Eight gives an idea of growing prosperous, because the letter () broadens gradually. * The Japanese thought of as a holy number in the ancient times. The reason is less well-understood, but it is thought that it is related to the fact they used eight to express large numbers vaguely such as (literally, eightfold and twentyfold), (literally, eight clouds), (literally, eight millions of Gods), etc. It is also guessed that the ancient Japanese gave importance to pairs, so some researchers guess twice as , which is also guessed to be a holy number in those times because it indicates the world (north, south, east, and west) might be considered a very holy number. * In
numerology Numerology (also known as arithmancy) is the belief in an occult, divine or mystical relationship between a number and one or more coinciding events. It is also the study of the numerical value, via an alphanumeric system, of the letters in ...
, 8 is the number of building, and in some theories, also the number of destruction.


In astrology

* In
astrology Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Di ...
, Scorpio is the 8th astrological sign of the
Zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The pa ...
. * In the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
, 8 was the number of "unmoving" stars in the sky, and symbolized the perfection of incoming planetary energy.


In music and dance

* A note played for one-eighth the duration of a whole note is called an
eighth note 180px, Figure 1. An eighth note with stem extending up, an eighth note with stem extending down, and an eighth rest. 180px, Figure 2. Four eighth notes beamed together. An eighth note (American) or a quaver ( British) is a musical note pla ...
, or quaver. * An
octave In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...
, the interval between two musical notes with the same letter name (where one has double the frequency of the other), is so called because there are eight notes between the two on a standard major or minor
diatonic scale In music theory, a diatonic scale is any heptatonic scale that includes five whole steps (whole tones) and two half steps (semitones) in each octave, in which the two half steps are separated from each other by either two or three whole st ...
, including the notes themselves and without chromatic deviation. The ecclesiastical
modes Mode ( la, modus meaning "manner, tune, measure, due measure, rhythm, melody") may refer to: Arts and entertainment * '' MO''D''E (magazine)'', a defunct U.S. women's fashion magazine * ''Mode'' magazine, a fictional fashion magazine which is ...
are ascending diatonic musical scales of eight notes or tones comprising an octave. * There are eight notes in the octatonic scale. * There are eight musicians in a double quartet or an
octet Octet may refer to: Music * Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble ** String octet, a piece of music written for eight string instruments *** Octet (Mendelssohn), 1825 com ...
. Both terms may also refer to a musical composition for eight voices or instruments. * Caledonians is a square dance for eight, resembling the
quadrille The quadrille is a dance that was fashionable in late 18th- and 19th-century Europe and its colonies. The quadrille consists of a chain of four to six '' contredanses''. Latterly the quadrille was frequently danced to a medley of opera melodie ...
. *
Album An album is a collection of audio recordings issued on compact disc (CD), vinyl, audio tape, or another medium such as digital distribution. Albums of recorded sound were developed in the early 20th century as individual 78 rpm records c ...
s with the number eight in their title include ''8'' by the Swedish band
Arvingarna Arvingarna is a Swedish dansband formed in Gothenburg in 1989. The group consists of Casper Janebrink (vocals and bass guitar), Lars Larsson (guitars, vocals and keyboards), Kim Carlsson (vocals and guitars) and Tommy Carlsson (drums and vocals). ...
, '' 8'' by the American rock band Incubus, '' The Meaning of 8'' by Minnesota indie rock band Cloud Cult and ''8ight'' by Anglo-American singer-songwriter Beatie Wolfe. *
Dream Theater Dream Theater is an American progressive metal band formed in 1985 under the name Majesty by John Petrucci, John Myung and Mike Portnoy while they attended Berklee College of Music in Boston, Massachusetts. They subsequently dropped out o ...
's eighth album ''
Octavarium ''Octavarium'' is the eighth studio album by American progressive metal band Dream Theater. Released on June 7, 2005, it was the band's final release with Atlantic Records. Recorded between September 2004 and February 2005, it was the last albu ...
'' contains many different references to the number 8, including the number of songs and various aspects of the music and cover artwork. * "Eight maids a-milking" is the gift on the eighth day of Christmas in the carol " The Twelve Days of Christmas". * The
8-track cartridge The 8-track tape (formally Stereo 8; commonly called eight-track cartridge, eight-track tape, and eight-track) is a magnetic tape sound recording technology that was popular from the mid-1960s to the early 1980s, when the compact cassette, whi ...
is a musical recording format. * "#8" is the stage name of Slipknot vocalist
Corey Taylor Corey Todd Taylor (born December 8, 1973) is an American musician, songwriter and actor. He is the lead vocalist of the heavy metal band Slipknot, in which he is designated #8, as well as the lead vocalist and guitarist for the rock band Ston ...
. * "Too Many Eights" is a song by Athens, Georgia's
Supercluster A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in t ...
. * Eight Seconds, a Canadian musical group popular in the 1980s with their most notable song "Kiss You (When It's Dangerous)". * "
Eight Days a Week "Eight Days a Week" is a song by the English rock band the Beatles. It was written by Paul McCartney and John Lennon based on McCartney's original idea. The song was released in the United Kingdom in December 1964 on the album '' Beatles for Sal ...
" is a #1 single for the music group
The Beatles The Beatles were an English Rock music, rock band, formed in Liverpool in 1960, that comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr. They are regarded as the Cultural impact of the Beatles, most influential band of al ...
. * ''Figure 8'' is the fifth studio album by singer-songwriter
Elliott Smith Steven Paul Smith (August 6, 1969 – October 21, 2003), known professionally as Elliott Smith, was an American singer-songwriter and multi-instrumentalist. Smith was born in Omaha, Nebraska, raised primarily in Texas, and lived much of hi ...
, released in the year 2000, an album released by Julia Darling in 1999, and an album released by Outasight in 2011. * Ming Hao from the k-pop group Seventeen goes by the name "The8". * "8 (circle)" is the eighth song on the album '' 22, A Million'' by the American band
Bon Iver Bon Iver ( ) is an American indie folk band founded in 2006 by singer-songwriter Justin Vernon. Vernon released Bon Iver's debut album, ''For Emma, Forever Ago,'' independently in July 2007. The majority of the album was recorded while Vernon ...
. * "8" is the eighth song on the album ''
When We All Fall Asleep, Where Do We Go? ''When We All Fall Asleep, Where Do We Go?'' (stylized in all caps) is the debut studio album by American singer and songwriter Billie Eilish. It was released on March 29, 2019, by Darkroom and Interscope Records in the US and Polydor Records i ...
'' by
Billie Eilish Billie Eilish Pirate Baird O'Connell ( ; born December 18, 2001) is an American singer-songwriter. She first gained public attention in 2015 with her debut single " Ocean Eyes", written and produced by her brother Finneas O'Connell, with whom ...
.


In film and television

* '' 8 Guys'' is a 2003 short film written and directed by
Dane Cook Dane Jeffrey Cook (born March 18, 1972) is an American stand-up comedian and film actor. He has released six comedy albums: '' Harmful If Swallowed''; ''Retaliation''; ''Vicious Circle''; '' Rough Around the Edges: Live from Madison Square Garde ...
. * '' 8 Man'' (or ''Eightman''): 1963 Japanese manga and anime superhero. * ''8 Mile'' is a 2002 film directed by Curtis Hanson. * ''8 mm'' is a 1999 film directed by
Joel Schumacher Joel T. Schumacher (; August 29, 1939June 22, 2020) was an American film director, producer and screenwriter. Raised in New York City by his mother, Schumacher graduated from Parsons School of Design and originally became a fashion designer. H ...
. * ''
8 Women ''8 Women'' (french: 8 femmes) is a 2002 dark comedy musical film written and directed by François Ozon. Based on the 1958 play by Robert Thomas, it features an ensemble cast of high-profile French actresses that includes Catherine Deneuve, Is ...
'' (Original French title: ) is a 2001 film directed by
François Ozon François Ozon (; born 15 November 1967) is a French film director and screenwriter. Ozon is considered one of the most important modern French filmmakers. His films are characterized by aesthetic beauty, sharp satirical humor and a free-wheeli ...
. * '' Eight Below'' is a 2006 film directed by Frank Marshall. * '' Eight Legged Freaks'' is a 2002 film directed by Ellory Elkayem. * '' Eight Men Out'' is a 1988 film directed by John Sayles. * ''
Jennifer Eight ''Jennifer 8'' is a 1992 American thriller film written and directed by Bruce Robinson and starring Andy García, Uma Thurman, and John Malkovich. Plot Former Los Angeles policeman John Berlin is teetering toward burnout after the collapse of ...
'', also known as ''Jennifer 8'', is a 1992 film written and directed by Bruce Robinson. * ''
Eight Is Enough ''Eight Is Enough'' is an American television comedy-drama series that ran on ABC from March 15, 1977, until May 23, 1981. The show was modeled on the life of syndicated newspaper columnist Tom Braden, a real-life parent with eight children, who ...
'' is an American television comedy-drama series. * In ''
Stargate SG-1 ''Stargate SG-1'' (often stylized in all caps, or abbreviated ''SG-1'') is a military science fiction adventure television series within Metro-Goldwyn-Mayer's ''Stargate'' franchise. The show, created by Brad Wright and Jonathan Glassner, ...
'' and '' Stargate Atlantis'', dialing an 8-chevron address will open a
wormhole A wormhole ( Einstein-Rosen bridge) is a hypothetical structure connecting disparate points in spacetime, and is based on a special solution of the Einstein field equations. A wormhole can be visualized as a tunnel with two ends at separate ...
to another galaxy. * '' The Hateful Eight'' is a 2015 American western mystery film written and directed by
Quentin Tarantino Quentin Jerome Tarantino (; born March 27, 1963) is an American film director, writer, producer, and actor. His films are characterized by stylized violence, extended dialogue, profanity, dark humor, non-linear storylines, cameos, ensembl ...
. * '' Kate Plus 8'' is an American reality television show.


In sports and other games

*
Eight-ball Eight-ball (also spelled 8-ball or eightball, and sometimes called solids and stripes, spots and stripes or rarely highs and lows) is a discipline of pool played on a billiard table with six pockets, cue sticks, and sixteen billiard balls ...
pool is played with a cue ball and 15 numbered balls, the black ball numbered 8 being the middle and most important one, as the winner is the player or side that legally pockets it after first pocketing its numerical group of 7 object balls (for other meanings see '' Eight ball (disambiguation)''). * In
chess Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to dist ...
, each side has eight pawns and the board is made of 64 squares arranged in an eight by eight lattice. The eight queens puzzle is a challenge to arrange eight queens on the board so that none can capture any of the others. * In the game of eights or
Crazy Eights Crazy Eights is a shedding-type card game for two to seven players and the best known American member of the Eights Group which also includes Pig and Spoons. The object of the game is to be the first player to discard all of their cards. The ga ...
, each successive player must play a card either of the same suit or of the same rank as that played by the preceding player, or may play an eight and call for any suit. The object is to get rid of all one's cards first. * In
association football Association football, more commonly known as football or soccer, is a team sport played between two teams of 11 players who primarily use their feet to propel the ball around a rectangular field called a pitch. The objective of the game is ...
, the number 8 has historically been the number of the Central Midfielder. * In
Australian rules football Australian football, also called Australian rules football or Aussie rules, or more simply football or footy, is a contact sport played between two teams of 18 players on an oval field, often a modified cricket ground. Points are scored by k ...
, the top eight teams at the end of the
Australian Football League The Australian Football League (AFL) is the only fully professional sports, professional competition of Australian rules football. Through the AFL Commission, the AFL also serves as the sport's governing body and is responsible for controlling ...
regular season qualify for the finals series (i.e. playoffs). * In
baseball Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding t ...
: ** The
center fielder A center fielder, abbreviated CF, is the outfielder in baseball who plays defense in center field – the baseball and softball fielding position between left field and right field. In the numbering system used to record defensive plays, the ...
is designated as number 8 for scorekeeping purposes. ** The
College World Series The College World Series (CWS), officially the NCAA Men's College World Series (MCWS), is an annual baseball tournament held in June in Omaha, Nebraska. The MCWS is the culmination of the National Collegiate Athletic Association (NCAA) Divisi ...
, the final phase of the NCAA Division I tournament, features eight teams. * In
rugby union Rugby union, commonly known simply as rugby, is a close-contact team sport that originated at Rugby School in the first half of the 19th century. One of the two codes of rugby football, it is based on running with the ball in hand. In it ...
, the only position without a proper name is the Number 8, a forward position. * In
rugby league Rugby league football, commonly known as just rugby league and sometimes football, footy, rugby or league, is a full-contact sport played by two teams of thirteen players on a rectangular field measuring 68 metres (75 yards) wide and 112 ...
: ** Most competitions (though not the
Super League The Super League (officially known as the Betfred Super League due to sponsorship from Betfred and legally known as Super League Europe), is the top-level of the British rugby league system. At present the league consists of twelve teams, of w ...
, which uses static squad numbering) use a position-based player numbering system in which one of the two starting props wears the number 8. ** The Australia-based
National Rugby League The National Rugby League (NRL) is an Australasian rugby league club competition which contains clubs from New South Wales, Queensland, Victoria, the Australian Capital Territory and New Zealand. The NRL formed in 1998 as a joint partnership ...
has its own 8-team finals series, similar but not identical in structure to that of the Australian Football League. * In
rowing Rowing is the act of propelling a human-powered watercraft using the sweeping motions of oars to displace water and generate reactional propulsion. Rowing is functionally similar to paddling, but rowing requires oars to be mechanically ...
, an "eight" refers to a sweep-oar racing boat with a crew of eight rowers plus a coxswain. * In the 2008 Games of the XXIX Olympiad held in
Beijing } Beijing ( ; ; ), Chinese postal romanization, alternatively romanized as Peking ( ), is the Capital city, capital of the China, People's Republic of China. It is the center of power and development of the country. Beijing is the world's Li ...
, the official opening was on 08/08/08 at 8:08:08 p.m. CST. * In Rock Climbing, climbers frequently use the Figure Eight knot to tie into their harnesses.


In foods

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Nestlé Nestlé S.A. (; ; ) is a Switzerland, Swiss multinational food and drink processing conglomerate corporation headquartered in Vevey, Vaud, Switzerland. It is the largest publicly held food company in the world, measured by revenue and other me ...
sells a brand of chocolates filled with peppermint-flavoured cream called
After Eight After Eight Mint Chocolate Thins, often referred to as simply "After Eights", are a brand of mint chocolate covered sugar confectionery. They were created by Rowntree Company Limited in the UK in 1962 and have been manufactured by Nestlé si ...
, referring to the time 8 p.m. * There are eight vegetables in V8 juice.


In literature

* Eights may refer to
octosyllabic The octosyllable or octosyllabic verse is a line of verse with eight syllables. It is equivalent to tetrameter verse in trochees in languages with a stress accent. Its first occurrence is in a 10th-century Old French saint's legend, the '' Vie ...
, usually iambic, lines of verse. * The drott-kvaett, an
Old Icelandic Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and their overseas settlement ...
verse, consisted of a stanza of eight regular lines. * In
Terry Pratchett Sir Terence David John Pratchett (28 April 1948 – 12 March 2015) was an English humourist, satirist, and author of fantasy novels, especially comical works. He is best known for his '' Discworld'' series of 41 novels. Pratchett's first no ...
's '' Discworld'' series, eight is a magical number and is considered taboo. Eight is not safe to be said by wizards on the Discworld and is the number of Bel-Shamharoth. Also, there are eight days in a Disc week and eight colours in a Disc spectrum, the eighth one being octarine. *
Lewis Carroll Charles Lutwidge Dodgson (; 27 January 1832 – 14 January 1898), better known by his pen name Lewis Carroll, was an English author, poet and mathematician. His most notable works are '' Alice's Adventures in Wonderland'' (1865) and its sequ ...
's poem ''
The Hunting of the Snark ''The Hunting of the Snark'', subtitled ''An Agony in 8 Fits'', is a poem by the English writer Lewis Carroll. It is typically categorised as a nonsense poem. Written between 1874 and 1876, it borrows the setting, some creatures, and eight ...
'' has 8 "fits" (cantos), which is noted in the full name "The Hunting of the Snark – ''An Agony, in Eight Fits''." * Eight apparitions appear to
Macbeth ''Macbeth'' (, full title ''The Tragedie of Macbeth'') is a tragedy by William Shakespeare. It is thought to have been first performed in 1606. It dramatises the damaging physical and psychological effects of political ambition on those w ...
in Act 4 scene 1 of Shakespeare's ''
Macbeth ''Macbeth'' (, full title ''The Tragedie of Macbeth'') is a tragedy by William Shakespeare. It is thought to have been first performed in 1606. It dramatises the damaging physical and psychological effects of political ambition on those w ...
'' as representations of the eight descendants of
Banquo Lord Banquo , the Thane of Lochaber, is a semi-historical character in William Shakespeare's 1606 play '' Macbeth''. In the play, he is at first an ally of Macbeth (both are generals in the King's army) and they meet the Three Witches tog ...
.


In slang

* An "eighth" is a common measurement of
marijuana Cannabis, also known as marijuana among other names, is a psychoactive drug from the cannabis plant. Native to Central or South Asia, the cannabis plant has been used as a drug for both recreational and entheogenic purposes and in various t ...
, meaning an eighth of an ounce. It is also a common unit of sale for psilocybin mushrooms. *
Avril Lavigne Avril Ramona Lavigne ( ; born September 27, 1984) is a Canadian singer and songwriter. At age 16, she signed a two-album recording contract with Arista Records. Her debut studio album, '' Let Go'' (2002), is the best-selling album of the 2 ...
's song " Sk8er Boi" uses this convention in the title. * "Section 8" is common U.S. slang for "crazy", based on the U.S. military's Section 8 discharge for mentally unfit personnel. * The Housing Choice Voucher Program, operated by the
United States Department of Housing and Urban Development The United States Department of Housing and Urban Development (HUD) is one of the executive departments of the U.S. federal government. It administers federal housing and urban development laws. It is headed by the Secretary of Housing and Ur ...
, is commonly referred to as the Section 8 program, as this was the original section of the Act which instituted the program. * In
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the ...
and
Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
, "volverse un ocho" (meaning to tie oneself in a figure 8) refers to getting in trouble or contradicting oneself. * In China, "8" is used in chat speak as a term for parting. This is due to the closeness in pronunciation of "8" (bā) and the English word "bye".


See also

*
The Magical Number Seven, Plus or Minus Two "The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information" is one of the most highly cited papers in psychology. It was written by the cognitive psychologist George A. Miller of Harvard University's D ...
*
List of highways numbered 8 The following highways are numbered 8. For roads numbered A8, see list of A8 roads. For roads numbered N8, see list of N8 roads. Route 8, or Highway 8, may refer to: International * Asian Highway 8 * European route E08 * European route E00 ...


References


External links


The Octonions
John C. Baez {{DEFAULTSORT:8 (Number) Integers 8 (number)