Kilo-

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kilo is a unit prefix in the metric system denoting multiplication by one thousand. It has been used in the International System of Units where it has the unit symbol k, in lower case.

The prefix kilo is derived from the Greek word χίλιοι (chilioi), meaning "thousand". It was originally adopted by Antoine Lavoisier's research group in 1795, and introduced into the metric system in France with its establishment in 1799.

Examples:

A second definition has been in common use in some fields of computer science and information technology, which is, however, inconsistent with the SI. It uses kilo as meaning 210 = 1024, because of the mathematical coincidence that 210 is approximately 103</�sup>. The NIST comments on this confusion: "Faced with this reality, the IEEE Standards Board decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes."[1]

Exponentiation [edit]

When units occur in exponentiation, such as in square and cubic forms, any multiplier prefix is considered part of the unit, and thus included in the exponentiation.

  • 1 km2 means one square kilometre or the area of a square of 1000 m by 1000 m or 106 m2.
  • 1 km3 means one cubic kilometre or the volume of a cube of 1000 m by 1000 m by 1000 m or 109 m3.

See also [edit]

References [edit]

Metric prefixes
Prefix Symbol 1000m 10n Decimal English word[n 1] Since[n 2]
yotta Y  10008  1024 1000000000000000000000000 septillion 1991
zetta Z  10007  1021 1000000000000000000000 sextillion 1991
exa E  10006  1018 1000000000000000000 quintillion 1975
peta P  10005  1015 1000000000000000 quadrillion 1975
tera T  10004  1012 1000000000000 trillion 1960
giga G  10003  109 1000000000 billion 1960
mega M  10002  106 1000000 million 1960
kilo k  10001  103 1000 thousand 1795
hecto h  10002/3  102 100 hundred 1795
deca da  10001/3  101 10 ten 1795
 10000  100 1 one
deci d  1000−1/3  10−1 0.1 tenth 1795
centi c  1000−2/3   10−2 0.01 hundredth 1795
milli m  1000−1  10−3 0.001 thousandth 1795
micro µ  1000−2  10−6 0.000001 millionth 1960
nano n  1000−3  10−9 0.000000001 billionth 1960
pico p  1000−4  10−12 0.000000000001 trillionth 1960
femto f  1000−5  10−15 0.000000000000001 quadrillionth 1964
atto a  1000−6  10−18 0.000000000000000001 quintillionth 1964
zepto z  1000−7  10−21 0.000000000000000000001 sextillionth 1991
yocto y  1000−8  10−24  0.000000000000000000000001 septillionth 1991
  1. ^ This table uses the short scale.
  2. ^ The metric system was introduced in 1795 with six prefixes. The other dates relate to recognition by a resolution of the CGPM.