TERA

For other uses, see Tera (disambiguation).

tera- (symbol: T) is a prefix in the SI system of units denoting 10¹², or 1 000 000 000 000.

Confirmed in 1960, it comes from the Greek τέρας, meaning monster. 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. For means of comparison, there are roughly 6*10²³ atoms, or 0.6 yotta-atoms, in 12 grams (1 mole) of the substance Carbon-12.

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.

See also

• SI prefix
• Binary prefix
• all pages from Tera