Atto
From Biocrawler, the free encyclopedia.
Atto- (symbol a) is an SI prefix to a unit and means that it is 10-18 times this unit. Examples are one attosecond or one attometre (U.S. spelling attometer).
Adopted in 1964, it comes from the Danish atten, meaning eighteen.
| 10n | Prefix | Symbol | Short scale | Long scale | Decimal Equivalent |
|---|---|---|---|---|---|
| 1024 | yotta | Y | Septillion | Quadrillion | 1 000 000 000 000 000 000 000 000 |
| 1021 | zetta | Z | Sextillion | Trilliard (thousand trillion) | 1 000 000 000 000 000 000 000 |
| 1018 | exa | E | Quintillion | Trillion | 1 000 000 000 000 000 000 |
| 1015 | peta | P | Quadrillion | Billiard (thousand billion) | 1 000 000 000 000 000 |
| 1012 | tera | T | Trillion | Billion | 1 000 000 000 000 |
| 109 | giga | G | Billion | Milliard (thousand million) | 1 000 000 000 |
| 106 | mega | M | Million | 1 000 000 | |
| 103 | kilo | k | Thousand | 1 000 | |
| 102 | hecto | h | Hundred | 100 | |
| 101 | deca, deka | da | Ten | 10 | |
| 100 | none | none | One | 1 | |
| 10−1 | deci | d | Tenth | 0.1 | |
| 10−2 | centi | c | Hundredth | 0.01 | |
| 10−3 | milli | m | Thousandth | 0.001 | |
| 10−6 | micro | µ | Millionth | 0.000 001 | |
| 10−9 | nano | n | Billionth | Milliardth | 0.000 000 001 |
| 10−12 | pico | p | Trillionth | Billionth | 0.000 000 000 001 |
| 10−15 | femto | f | Quadrillionth | Billiardth | 0.000 000 000 000 001 |
| 10−18 | atto | a | Quintillionth | Trillionth | 0.000 000 000 000 000 001 |
| 10−21 | zepto | z | Sextillionth | Trilliardth | 0.000 000 000 000 000 000 001 |
| 10−24 | yocto | y | Septillionth | Quadrillionth | 0.000 000 000 000 000 000 000 001 |
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See also
es:Atto fr:Atto it:Atto (prefisso) nl:Atto no:Atto pl:Atto sl:Ato vi:Atô
