Peta-

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This article is about the SI prefix. For other uses, see Peta (disambiguation).

Peta /ˈpɛ.tə/ is a decimal unit prefix in the metric system denoting multiplication by 1015 (1000000000000000). It was adopted as an SI prefix in the International System of Units in 1975,[1] and has the symbol P.

Peta is derived from the Greek πέντε, meaning "five". It denotes the fifth power of 1000 (10005). It is similar to the prefix penta ("five"), but without the letter n (on the analogy of the prefix tera (from the Greek for "monster") for 10004 looking like tetra- ("four") with a letter missing).

Examples:

Prefix 1000m 10n Decimal English word Adoption[nb 1]
Name Symbol Short scale Long scale
yotta Y  10008  1024 1000000000000000000000000 1991
zetta Z  10007  1021 1000000000000000000000 1991
exa E  10006  1018 1000000000000000000  trillion 1975
peta P  10005  1015 1000000000000000  billiard 1975
tera T  10004  1012 1000000000000  trillion  billion 1960
giga G  10003  109 1000000000  billion  milliard 1960
mega M  10002  106 1000000             million 1873
kilo k  10001  103 1000 1795
hecto h  10002/3  102 100 1795
deca da  10001/3  101 10 1795
 10000  100 1
deci d  1000−1/3  10−1 0.1 1795
centi c  1000−2/3   10−2 0.01 1795
milli m  1000−1  10−3 0.001 1795
micro μ  1000−2  10−6 0.000001             millionth 1873
nano n  1000−3  10−9 0.000000001  billionth 1960
pico p  1000−4  10−12 0.000000000001  trillionth  billionth 1960
femto f  1000−5  10−15 0.000000000000001 1964
atto a  1000−6  10−18 0.000000000000000001  trillionth 1964
zepto z  1000−7  10−21 0.000000000000000000001 1991
yocto y  1000−8  10−24  0.000000000000000000000001 1991
  1. ^ Prefixes adopted before 1960 already existed before SI. 1873 was the introduction of the CGS system.

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