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Look up deca- in Wiktionary, the free dictionary. |
deca or deka[1] is an SI prefix (symbol da) in the SI system of units, also a numerical prefix (from Greek δέκα), denoting a factor of 101 or ten.
The prefix was a part of the original metric system in 1795. It is not in very common usage in English-speaking countries, although the decapascal is occasionally used by audiologists. The decanewton is also encountered occasionally, probably because it is an SI approximation of the kilogram-force. It is more commonly used in other languages: in Austrian and Hungarian, deca is common (and always means decagram).
Before the symbol was standardized as da with the introduction of the SI in 1960, various other symbols were more common, such as "dk", "D", and "Da".
| 1000m | 10n | Prefix | Symbol | Since[1] | Short scale | Long scale | Decimal |
|---|---|---|---|---|---|---|---|
| 10008 | 1024 | yotta | Y | 1991 | Septillion | Quadrillion | 1000000000000000000000000 |
| 10007 | 1021 | zetta | Z | 1991 | Sextillion | Trilliard | 1000000000000000000000 |
| 10006 | 1018 | exa | E | 1975 | Quintillion | Trillion | 1000000000000000000 |
| 10005 | 1015 | peta | P | 1975 | Quadrillion | Billiard | 1000000000000000 |
| 10004 | 1012 | tera | T | 1960 | Trillion | Billion | 1000000000000 |
| 10003 | 109 | giga | G | 1960 | Billion | Milliard | 1000000000 |
| 10002 | 106 | mega | M | 1960 | Million | 1 000 000 | |
| 10001 | 103 | kilo | k | 1795 | Thousand | 1000 | |
| 10002⁄3 | 102 | hecto | h | 1795 | Hundred | 100 | |
| 10001⁄3 | 101 | deca | da | 1795 | Ten | 10 | |
| 10000 | 100 | (none) | (none) | NA | One | 1 | |
| 1000−1⁄3 | 10−1 | deci | d | 1795 | Tenth | 0.1 | |
| 1000−2⁄3 | 10−2 | centi | c | 1795 | Hundredth | 0.01 | |
| 1000−1 | 10−3 | milli | m | 1795 | Thousandth | 0.001 | |
| 1000−2 | 10−6 | micro | µ | 1960[2] | Millionth | 0.000001 | |
| 1000−3 | 10−9 | nano | n | 1960 | Billionth | Milliardth | 0.000000001 |
| 1000−4 | 10−12 | pico | p | 1960 | Trillionth | Billionth | 0.000000000001 |
| 1000−5 | 10−15 | femto | f | 1964 | Quadrillionth | Billiardth | 0.000000000000001 |
| 1000−6 | 10−18 | atto | a | 1964 | Quintillionth | Trillionth | 0.000000000000000001 |
| 1000−7 | 10−21 | zepto | z | 1991 | Sextillionth | Trilliardth | 0.000000000000000000001 |
| 1000−8 | 10−24 | yocto | y | 1991 | Septillionth | Quadrillionth | 0.000000000000000000000001 |
References
- ^ Guide for the Use of the International System of Units (SI), 1995, NIST Special Publication 811[1]
See also
External links
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