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"Yocto" redirects here. For the Linux Foundation workgroup, see
Yocto Project.
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Look up yocto in Wiktionary, the free dictionary. |
Yocto (symbol y) is a unit prefix in the metric system denoting a factor of 10−24 or 0.000000000000000000000001.
It was adopted in 1991[1] by the General Conference on Weights and Measures. It comes from the Latin/Greek octo (οκτώ), meaning "eight", because it is equal to 1000−8. As of 2015, yocto is the smallest official SI prefix.
It can be used to state a subatomic particle's mass, for example:
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|
Prefix |
1000m |
10n |
Decimal |
English word |
Adoption[nb 1] |
Name |
Symbol |
Short scale |
Long scale |
yotta |
Y |
10008 |
1024 |
1000000000000000000000000 |
septillion |
quadrillion |
1991 |
zetta |
Z |
10007 |
1021 |
1000000000000000000000 |
sextillion |
thousand trillion or trilliard |
1991 |
exa |
E |
10006 |
1018 |
1000000000000000000 |
quintillion |
trillion |
1975 |
peta |
P |
10005 |
1015 |
1000000000000000 |
quadrillion |
thousand billion or billiard |
1975 |
tera |
T |
10004 |
1012 |
1000000000000 |
trillion |
billion |
1960 |
giga |
G |
10003 |
109 |
1000000000 |
billion |
thousand million or milliard |
1960 |
mega |
M |
10002 |
106 |
1000000 |
million |
1960 (1873) |
kilo |
k |
10001 |
103 |
1000 |
thousand |
1960 (1795) |
hecto |
h |
10002/3 |
102 |
100 |
hundred |
1960 (1795) |
deca |
da |
10001/3 |
101 |
10 |
ten |
1960 (1795) |
|
10000 |
100 |
1 |
one |
– |
deci |
d |
1000−1/3 |
10−1 |
0.1 |
tenth |
1960 (1795) |
centi |
c |
1000−2/3 |
10−2 |
0.01 |
hundredth |
1960 (1795) |
milli |
m |
1000−1 |
10−3 |
0.001 |
thousandth |
1960 (1795) |
micro |
μ |
1000−2 |
10−6 |
0.000001 |
millionth |
1960 (1873) |
nano |
n |
1000−3 |
10−9 |
0.000000001 |
billionth |
thousand millionth |
1960 |
pico |
p |
1000−4 |
10−12 |
0.000000000001 |
trillionth |
billionth |
1960 |
femto |
f |
1000−5 |
10−15 |
0.000000000000001 |
quadrillionth |
thousand billionth |
1964 |
atto |
a |
1000−6 |
10−18 |
0.000000000000000001 |
quintillionth |
trillionth |
1964 |
zepto |
z |
1000−7 |
10−21 |
0.000000000000000000001 |
sextillionth |
thousand trillionth |
1991 |
yocto |
y |
1000−8 |
10−24 |
0.000000000000000000000001 |
septillionth |
quadrillionth |
1991 |
|
|
- ↑ The metric system was introduced in 1795 with several metric prefixes, of which, however, only six were adopted as SI prefixes by the 11th CGPM conference in 1960, whereas myria (104) as well as double and demi were not adopted. In 1873, micro and mega were recommended by the British Association for the Advancement of Science. The other dates relate to recognition by a resolution of the CGPM.
References