Hecto-

Hecto (symbol: h) is a decimal unit prefix in the metric system denoting a factor of one hundred. It was adopted as a multiplier in 1795, and comes from the Greek ἑκατόν ékatón, meaning "hundred". In 19th century English it was sometimes spelled hecato, in line with a puristic opinion by Thomas Young.[1][2] Its unit symbol as an SI prefix in the International System of Units (SI) is the lower case letter h.

It is rarely used except in certain specific applications:

SI prefixes
Prefix Base 10 Decimal English word Adoption[nb 1]
Name Symbol Short scale Long scale
yotta- Y-  1024 1000000000000000000000000  septillion  quadrillion 1991
zetta- Z-  1021 1000000000000000000000  sextillion  trilliard 1991
exa- E-  1018 1000000000000000000  quintillion  trillion 1975
peta- P-  1015 1000000000000000  quadrillion  billiard 1975
tera- T-  1012 1000000000000  trillion  billion 1960
giga- G-  109 1000000000  billion  milliard 1960
mega- M-  106 1000000  million 1873
kilo- k-  103 1000  thousand 1795
hecto- h-  102 100  hundred 1795
deca- da-  101 10  ten 1795
 100 1  one
deci- d-  10−1 0.1  tenth 1795
centi- c-  10−2 0.01  hundredth 1795
milli- m-  10−3 0.001  thousandth 1795
micro- μ-  10−6 0.000001  millionth 1873
nano- n-  10−9 0.000000001  billionth  milliardth 1960
pico- p-  10−12 0.000000000001  trillionth  billionth 1960
femto- f-  10−15 0.000000000000001  quadrillionth  billiardth 1964
atto- a-  10−18 0.000000000000000001  quintillionth  trillionth 1964
zepto- z-  10−21 0.000000000000000000001  sextillionth  trilliardth 1991
yocto- y-  10−24  0.000000000000000000000001  septillionth  quadrillionth 1991
  1. Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873.

See also

References

  1. Brewster, David (1832). The Edinburgh Encyclopaedia. 12 (1st American ed.). Joseph and Edward Parker. Retrieved 2015-10-09.
  2. Dingler, Johann Gottfried (1823). Polytechnisches Journal (in German). 11. Stuttgart, Germany: J.W. Gotta'schen Buchhandlung. Retrieved 2015-10-09.
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