Tera-
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Tera- (symbol: T) is a prefix in the SI system of units denoting 1012, or 1,000,000,000,000 (1 million million).
Confirmed in 1960, it comes from the Greek τέρας, meaning monster.[1] It also bears a resemblance to the Greek prefix τετρα- meaning four; the coincidence of it signifying the fourth power of 1000 served as a model for the higher-order prefixes peta-, exa-, zetta- and yotta-, all of which are deliberately distorted forms of the Latin or Greek roots for the corresponding powers (fifth to eighth respectively) of 1000.
In computer science tera- can sometimes mean 1,099,511,627,776 (240) instead of 1,000,000,000,000, especially in the term terabyte. To avoid this ambiguity, the binary prefix tebi- has been introduced to signify 240, but this, in common with the other binary prefixes, is not currently in general use.
| 1000n | 10n | Prefix | Symbol | Since[1] | Short scale | Long scale | Decimal equivalent in SI writing style |
|---|---|---|---|---|---|---|---|
| 10008 | 1024 | yotta- | Y | 1991 | Septillion | Quadrillion | 1 000 000 000 000 000 000 000 000 |
| 10007 | 1021 | zetta- | Z | 1991 | Sextillion | Trilliard (thousand trillion) | 1 000 000 000 000 000 000 000 |
| 10006 | 1018 | exa- | E | 1975 | Quintillion | Trillion | 1 000 000 000 000 000 000 |
| 10005 | 1015 | peta- | P | 1975 | Quadrillion | Billiard (thousand billion) | 1 000 000 000 000 000 |
| 10004 | 1012 | tera- | T | 1960 | Trillion | Billion | 1 000 000 000 000 |
| 10003 | 109 | giga- | G | 1960 | Billion | Milliard (thousand million) | 1 000 000 000 |
| 10002 | 106 | mega- | M | 1960 | Million | 1 000 000 | |
| 10001 | 103 | kilo- | k | 1795 | Thousand | 1 000 | |
| 10002/3 | 102 | hecto- | h | 1795 | Hundred | 100 | |
| 10001/3 | 101 | deca- | da | 1795 | Ten | 10 | |
| 10000 | 100 | (none) | (none) | NA | One | 1 | |
| 1000−1/3 | 10−1 | deci- | d | 1795 | Tenth | 0.1 | |
| 1000−2/3 | 10−2 | centi- | c | 1795 | Hundredth | 0.01 | |
| 1000−1 | 10−3 | milli- | m | 1795 | Thousandth | 0.001 | |
| 1000−2 | 10−6 | micro- | µ | 1960[2] | Millionth | 0.000 001 | |
| 1000−3 | 10−9 | nano- | n | 1960 | Billionth | Milliardth | 0.000 000 001 |
| 1000−4 | 10−12 | pico- | p | 1960 | Trillionth | Billionth | 0.000 000 000 001 |
| 1000−5 | 10−15 | femto- | f | 1964 | Quadrillionth | Billiardth | 0.000 000 000 000 001 |
| 1000−6 | 10−18 | atto- | a | 1964 | Quintillionth | Trillionth | 0.000 000 000 000 000 001 |
| 1000−7 | 10−21 | zepto- | z | 1991 | Sextillionth | Trilliardth | 0.000 000 000 000 000 000 001 |
| 1000−8 | 10−24 | yocto- | y | 1991 | Septillionth | Quadrillionth | 0.000 000 000 000 000 000 000 001 |
| Notes: 1. The 1795 dates identify prefixes in use since the metric system was introduced. The other dates are not necessarily dates of first use, but rather the date of recognition by a resolution of the CGPM, which first met in 1889. 2. The micron was earlier recognized by the CGPM in 1948; that decision was abrogated in 1967-68. | |||||||
[edit] References
- ^ YourDictionary.com, tera-, Retrieved on 2007-06-05.
[edit] See also
ca:Tera cs:Tera et:Tera- fa:ترا fr:Téra ko:테라 it:Tera (prefisso) he:טרה (תחילית) mk:Тера nl:Tera ja:テラ no:Tera nds:Tera pl:Tera pt:Tera sl:Tera sr:Тера (префикс) fi:Tera sv:Tera vi:Têra zh:兆
