Deca (and dec), sometimes deka, is a common

English-language English is a West Germanic language that developed in early medieval England and has since become a English as a lingua franca, global lingua franca. The namesake of the language is the Angles (tribe), Angles, one of the Germanic peoples th ...

numeral prefix derived from the

Late Latin Late Latin is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the 3rd to 6th centuries CE, and continuing into the 7th century in ...

("(set of) ten"), from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

, from (déka, " ten"). It is used in many words. It is also a

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 (''decimal fractions'') of th ...

unit prefix A unit prefix is a specifier or mnemonic that is added to the beginning of a unit of measurement to indicate multiples or fractions of the units. Units of various order of magnitude, sizes are commonly formed by the use of such prefixes. The Metric ...

in the

International System of Units The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official s ...

(SI) denoting a factor of ten, with symbol da and spelled "deca" internationally (or "deka" in

American spelling Despite the various list of dialects of English, English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variati ...

''Guide for the Use of the International System of Units (SI)''
1995, NIST Special Publication 811).

SI

The prefix was a part of the original metric system in 1795. It is not in very common usage, although the deca pascal is occasionally used by audiologists. The deca newton is also encountered occasionally, probably because it is an SI approximation of the

kilogram-force The kilogram-force (kgf or kgF), or kilopond (kp, from ), is a non-standard Gravitational metric system, gravitational metric unit of force. It is not accepted for use with the International System of Units (SI) and is deprecated for most uses. T ...

. Its use is more common in

Central Europe Central Europe is a geographical region of Europe between Eastern Europe, Eastern, Southern Europe, Southern, Western Europe, Western and Northern Europe, Northern Europe. Central Europe is known for its cultural diversity; however, countries in ...

. In German, Polish, Czech, Slovak, and Hungarian, ''deka'' (or ''deko'') is common, and used in self-standing form, always meaning '' decagram''. A

runway In aviation, a runway is an elongated, rectangular surface designed for the landing and takeoff of an aircraft. Runways may be a human-made surface (often asphalt concrete, asphalt, concrete, or a mixture of both) or a natural surface (sod, ...

number typically indicates its

magnetic Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, m ...

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

in decadegrees. Before the symbol as an

SI prefix The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official st ...

was standardized as ''da'' with the introduction of the

in 1960, various other symbols were more common, such as ''dk'' (e.g., UK and Austria), ''D'' (e.g., Germany, Eastern Europe), and ''Da''. For syntactical reasons, the HP 48, 49, 50 series, as well as the HP 39gII and

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 ...

calculators use the unit prefix ''D''. * 1 decametre = 10

metre The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of ...

s * 1 decalitre = 10

litre The litre ( Commonwealth spelling) or liter ( American spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metres (m3). A ...

s * 1 decare = 10 ares Examples: * The

blue whale The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known ever to have existed. The blue whale's long and slender body can ...

is approximately 30 metres or 3 decametres in length.

As an English prefix

The prefix is used in many words.

General

Decathlon The decathlon is a combined event in athletics consisting of 10 track and field events. The word "decathlon" was formed, in analogy to the word "pentathlon", from Greek δέκα (''déka'', meaning "ten") and ἄθλος (''áthlos'', or ἄ ...

, a combined event in athletics consisting of ten track and field events. *

Decennial An anniversary is the date on which an event took place or an institution was founded. Most countries celebrate national anniversaries, typically called national days. These could be the List of national independence days, date of independen ...

, ten-yearly or a celebration of ten years.

Mathematics

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 (''decimal fractions'') of th ...

based on the number ten. * Decagon a plane figure with ten sides * Decahedron a polyhedron with ten faces

Chemistry

* Decane, a hydrocarbon with 10 carbon atoms

Biology

Decapoda The Decapoda or decapods, from Ancient Greek δεκάς (''dekás''), meaning "ten", and πούς (''poús''), meaning "foot", is a large order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, a ...

, an order of crustaceans with ten feet

Religion

* The

Decalogue The Ten Commandments (), or the Decalogue (from Latin , from Ancient Greek , ), are religious and ethical directives, structured as a covenant document, that, according to the Hebrew Bible, were given by YHWH to Moses. The text of the Ten C ...

SI

As an English prefix

General

Mathematics

Chemistry

Biology

Religion

See also

Notes

References

External links