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Deci- (symbol d) is a decimal unit prefix in the metric system denoting a factor of one tenth. Proposed in 1793,[1] and adopted in 1795, the prefix comes from the Latin decimus, meaning "tenth". Since 1960, the prefix is part of the International System of Units (SI).[2][3]
A frequent use of the prefix is in the unit deciliter (dl), common in food recipes; many European homes have a deciliter measure for flour, water, etc. A common measure in engineering is the unit decibel for measuring ratios of power and root-power quantities, such as sound level and electrical amplification.
Prefix | Base 10 | Decimal | Adoption [nb 1] | |
---|---|---|---|---|
Name | Symbol | |||
quetta | Q | 1030 | 1000000000000000000000000000000 | 2022[5] |
ronna | R | 1027 | 1000000000000000000000000000 | |
yotta | Y | 1024 | 1000000000000000000000000 | 1991 |
zetta | Z | 1021 | 1000000000000000000000 | |
exa | E | 1018 | 1000000000000000000 | 1975[6] |
peta | P | 1015 | 1000000000000000 | |
tera | T | 1012 | 1000000000000 | 1960 |
giga | G | 109 | 1000000000 | |
mega | M | 106 | 1000000 | 1873 |
kilo | k | 103 | 1000 | 1795 |
hecto | h | 102 | 100 | |
deca | da | 101 | 10 | |
— | — | 100 | 1 | — |
deci | d | 10−1 | 0.1 | 1795 |
centi | c | 10−2 | 0.01 | |
milli | m | 10−3 | 0.001 | |
micro | μ | 10−6 | 0.000001 | 1873 |
nano | n | 10−9 | 0.000000001 | 1960 |
pico | p | 10−12 | 0.000000000001 | |
femto | f | 10−15 | 0.000000000000001 | 1964 |
atto | a | 10−18 | 0.000000000000000001 | |
zepto | z | 10−21 | 0.000000000000000000001 | 1991 |
yocto | y | 10−24 | 0.000000000000000000000001 | |
ronto | r | 10−27 | 0.000000000000000000000000001 | 2022[5] |
quecto | q | 10−30 | 0.000000000000000000000000000001 | |
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