Gamma (uppercase , lowercase ; ''gámma'') is the third letter of the
Greek alphabet
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BCE. It is derived from the earlier Phoenician alphabet, and was the earliest known alphabetic script to have distinct letters for vowels as ...
. In the system of
Greek numerals
Greek numerals, also known as Ionic, Ionian, Milesian, or Alexandrian numerals, are a system of writing numbers using the letters of the Greek alphabet. In modern Greece, they are still used for ordinal numbers and in contexts similar to those ...
it has a value of 3. In
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...
, the letter gamma represented a
voiced velar stop . In
Modern Greek
Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the dialects of the Greek language spoken in the modern era, including the official standardized form of the ...
, this letter represents either a
voiced velar fricative or a
voiced palatal fricative (while /g/ in foreign words is instead commonly transcribed as γκ).
In the
International Phonetic Alphabet
The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic notation based primarily on the Latin script. It was devised by the International Phonetic Association in the late 19th century as a standardized representation ...
and other modern Latin-alphabet based
phonetic notations, it represents the voiced velar fricative.
History
The Greek letter Gamma Γ is a grapheme derived from the
Phoenician letter (''gīml'') which was rotated from the
right-to-left script of Canaanite to accommodate the Greek language's writing system of left-to-right. The Canaanite
grapheme
In linguistics, a grapheme is the smallest functional unit of a writing system.
The word ''grapheme'' is derived and the suffix ''-eme'' by analogy with ''phoneme'' and other names of emic units. The study of graphemes is called '' graphemi ...
represented the /g/ phoneme in the
Canaanite language, and as such is cognate with ''
gimel
Gimel is the third letter of the Semitic abjads, including Phoenician Gīml , Hebrew Gimel , Aramaic Gāmal , Syriac Gāmal , and Arabic (in alphabetical order; fifth in spelling order). Its sound value in the original Phoenician and in all ...
'' ג of the
Hebrew alphabet
The Hebrew alphabet ( he, אָלֶף־בֵּית עִבְרִי, ), known variously by scholars as the Ktav Ashuri, Jewish script, square script and block script, is an abjad script used in the writing of the Hebrew language and other Jewi ...
.
Based on its name, the letter has been interpreted as an abstract representation of a
camel's neck, but this has been criticized as contrived, and it is more likely that the letter is derived from an Egyptian hieroglyph representing a club or
throwing stick.
In
Archaic Greece, the shape of gamma was closer to a classical
lambda
Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave ri ...
(Λ), while lambda retained the Phoenician
L-shape ().
Letters that arose from the Greek gamma include
Etruscan (Old Italic) 𐌂,
Roman
Roman or Romans most often refers to:
* Rome, the capital city of Italy
* Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of ancient Rome
*''Epistle to the Romans'', shortened to ''Romans'', a lett ...
C and
G,
Runic ''
kaunan'' ,
Gothic
Gothic or Gothics may refer to:
People and languages
*Goths or Gothic people, the ethnonym of a group of East Germanic tribes
**Gothic language, an extinct East Germanic language spoken by the Goths
**Crimean Gothic, the Gothic language spoken b ...
''geuua'' , the
Coptic Ⲅ, and the
Cyrillic letters
Г and
Ґ.
Greek phoneme
The Ancient Greek /g/ phoneme was the voiced velar stop, continuing the reconstructed
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 ...
''*g'', ''*ǵ''.
The modern Greek phoneme represented by gamma is realized either as a
voiced palatal fricative () before a
front vowel (/e/, /i/), or as a
voiced velar fricative in all other environments. Both in Ancient and in Modern Greek, before other
velar consonant
Velars are consonants place of articulation, articulated with the back part of the tongue (the dorsum) against the soft palate, the back part of the roof of the mouth (known also as the Soft palate, velum).
Since the velar region of the roof of ...
s (κ, χ, ξ ''k, kh, ks''), gamma represents a
velar nasal . A double gamma γγ represents the sequence (phonetically varying ) or .
Phonetic transcription
Lowercase Greek gamma is used in the
Americanist phonetic notation
Americanist phonetic notation, also known as the North American Phonetic Alphabet (NAPA), the Americanist Phonetic Alphabet or the American Phonetic Alphabet (APA), is a system of phonetic notation originally developed by European and American ...
and
Uralic Phonetic Alphabet to indicate voiced consonants.
The gamma was also added to the Latin alphabet, as
Latin gamma
The Latin letter gamma, Ɣ (minuscule: ɣ), is a letter used in some orthographies based on the Latin alphabet. Its uppercase and lowercase shape is based on the lowercase shape of the Greek letter gamma (γ). Unlike the Greek gamma, the Lati ...
, in the following forms: majuscule Ɣ, minuscule ɣ, and superscript modifier letter ˠ.
In the
International Phonetic Alphabet
The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic notation based primarily on the Latin script. It was devised by the International Phonetic Association in the late 19th century as a standardized representation ...
the minuscule letter is used to represent a
voiced velar fricative and the superscript modifier letter is used to represent
velarization. It is not to be confused with the character , which looks like a lowercase Latin gamma that lies above the
baseline rather than crossing, and which represents the
close-mid back unrounded vowel. In certain
nonstandard variations of the IPA, the uppercase form is used.
It is as a full-fledged majuscule and minuscule letter in the alphabets of some of
languages of Africa such as
Dagbani
Dagbani (or Dagbane), also known as Dagbanli and Dagbanle, is a Gur language spoken in Ghana and Northern Togo. Its native speakers are estimated around 3,160,000. It is a compulsory subject in primary and junior high school in the Dagbon King ...
,
Dinka,
Kabye, and
Ewe, and
Berber languages using the
Berber Latin alphabet.
It is sometimes also used in the romanization of
Pashto
Pashto (,; , ) is an Eastern Iranian language in the Indo-European language family. It is known in historical Persian literature as Afghani ().
Spoken as a native language mostly by ethnic Pashtuns, it is one of the two official langua ...
.
Mathematics and science
Lowercase
The lowercase letter
is used as a symbol for:
*
Chromatic number of in
graph theory
In mathematics, graph theory is the study of '' graphs'', which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of '' vertices'' (also called ''nodes'' or ''points'') which are conn ...
*
Gamma radiation in
nuclear physics
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter.
Nuclear physics should not be confused with atomic physics, which studies t ...
*The
photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they alwa ...
, the elementary particle of light and other
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
*The 434 nm
spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to ident ...
in the
Balmer series
*
Surface energy in
materials science
*The
Lorentz factor in the
theory of relativity
*In mathematics, the
lower incomplete gamma function
*The
heat capacity ratio ''C
p''  /''C
v'' in
thermodynamics
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws ...
*The
activity coefficient
In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. In an ideal mixture, the microscopic interactions between each pair of chemical species are the same ...
in
thermodynamics
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws ...
*The
gyromagnetic ratio in
electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...
*
Gamma wave
A gamma wave or gamma Rhythm is a pattern of neural oscillation in humans with a frequency between 25 and 140 Hz, the 40- Hz point being of particular interest. Gamma rhythms are correlated with large scale brain network activity and cognitive ...
s in
neuroscience
Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary science that combines physiology, an ...
*
Gamma motor neurons in
neuroscience
Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary science that combines physiology, an ...
*A non-
SI metric unit of measure of
mass
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different ele ...
equal to one
microgram (1 μg).
This always-rare use is currently deprecated.
*A non-
SI unit of measure of
magnetic flux density, sometimes used in
geophysics
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' so ...
, equal to 1
nano tesla (nT).
*The power by which the luminance of an image is increased in
gamma correction
Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression:
: V_\tex ...
*The
Euler–Mascheroni constant
*In civil and mechanical engineering:
**
Specific weight
**The
shear rate of a fluid is represented by a lowercase gamma with a dot above it:
**
Austenite
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 100 ...
(also known as γ-iron), a metallic non-magnetic allotrope or solid solution of iron.
*The gamma carbon, the third carbon attached to a
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the r ...
in
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J ...
and
biochemistry
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...
; see
Alpha and beta carbon
The lowercase Latin gamma ɣ can also be used in contexts (such as chemical or molecule nomenclature) where gamma must not be confused with the letter
y, which can occur in some computer typefaces.
Uppercase
The uppercase letter
is used as a symbol for:
*In mathematics, the
gamma function
In mathematics, the gamma function (represented by , the capital letter gamma from the Greek alphabet) is one commonly used extension of the factorial function to complex numbers. The gamma function is defined for all complex numbers excep ...
(usually written as
-function) is an extension of the
factorial to
complex number
In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the fo ...
s
*In mathematics, the
upper incomplete gamma function
In mathematics, the upper and lower incomplete gamma functions are types of special functions which arise as solutions to various mathematical problems such as certain integrals.
Their respective names stem from their integral definitions, whic ...
*The
Christoffel symbols in differential geometry
*In probability theory and statistics, the
gamma distribution
In probability theory and statistics, the gamma distribution is a two- parameter family of continuous probability distributions. The exponential distribution, Erlang distribution, and chi-square distribution are special cases of the gamma di ...
is a two-parameter family of continuous probability distributions.
*In
solid-state physics, the center of the
Brillouin zone
*
Circulation in
fluid mechanics
Fluid mechanics is the branch of physics concerned with the mechanics of fluids ( liquids, gases, and plasmas) and the forces on them.
It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical and ...
*As
reflection coefficient
In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected ...
in physics and electrical engineering
*The tape alphabet of a
Turing machine
A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer alg ...
*The
Feferman–Schütte ordinal
In mathematics, the Feferman–Schütte ordinal Γ0 is a large countable ordinal.
It is the proof-theoretic ordinal of several mathematical theories, such as arithmetical transfinite recursion.
It is named after Solomon Feferman and Kurt Schütte ...
*One of the
Greeks in mathematical finance
Meteorology
Tropical cyclones
The name Gamma has been used twice for tropical cyclones:
Tropical Storm Gamma (2005) - deadly tropical storm that impacted Honduras
Hurricane Gamma
Hurricane Gamma was a Category 1 hurricane that brought heavy rains, flooding, and landslides to the Yucatán Peninsula in early October 2020. The twenty-fifth depression, twenty-fourth named storm and ninth hurricane of the extremely active 202 ...
(
2020) - hurricane that affected the Yucatan Peninsula
Encoding
HTML
The
HTML entities
In SGML, HTML and XML documents, the logical constructs known as ''character data'' and ''attribute values'' consist of sequences of characters, in which each character can manifest directly (representing itself), or can be represented by a series ...
for uppercase and lowercase gamma are
Γ
and
γ
.
Unicode
* Greek Gamma
* Coptic Gamma
*
Latin Gamma
The Latin letter gamma, Ɣ (minuscule: ɣ), is a letter used in some orthographies based on the Latin alphabet. Its uppercase and lowercase shape is based on the lowercase shape of the Greek letter gamma (γ). Unlike the Greek gamma, the Lati ...
/
phonetic Gamma
* CJK Square Gamma
* Technical / Mathematical Gamma
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
See also
*
Г, г - Ge (Cyrillic)
*
G, g - Latin
*
Gamma correction
Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression:
: V_\tex ...
*
Gammadion – symbol that appears to look like a swastika, but pre-dates the Nazi Hakenkreuz (Hooked-Cross)
References
{{reflist
Greek letters
Gz