Zetta (unit symbol prefix Z) is a decimal unit prefix in the metric system denoting a factor of 1021 or 1000000000000000000000. The prefix was added as an SI prefix to the International System of Units (SI) in 1991.
Zetta is derived from the Latin numeral septem 'seven', and represents 10007.[1]
A prefix of the same value, hepta, derived from the Ancient Greek ἑπτά (hepta) 'seven', was informally introduced a few years before the promulgation of zetta, but never received official sanction and is considered obsolete.[citation needed]
Examples:
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 | |
|
1018 to 1023
1021 | Zetta- (ZJ) | 6.9×1021 J | Estimated energy contained in the world's natural gas reserves as of 2010[7][8] |
7.9×1021 J | Estimated energy contained in the world's petroleum reserves as of 2010[7][9] |