Tera-

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This article describes the SI prefix. For other meanings, see Tera.

Look up tera- in
Wiktionary, the free dictionary.

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

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 1,000.

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.

SI prefixes
1000^m	10ⁿ	Prefix	Symbol	Since^[1]	Short scale	Long scale	Decimal
1000⁸	10²⁴	yotta-	Y	1991	Septillion	Quadrillion	1 000 000 000 000 000 000 000 000
1000⁷	10²¹	zetta-	Z	1991	Sextillion	Trilliard	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	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	1 000 000 000
1000²	10⁶	mega-	M	1960	Million		1 000 000
1000¹	10³	kilo-	k	1795	Thousand		1 000
1000^2/3	10²	hecto-	h	1795	Hundred		100
1000^1/3	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
The metric system was introduced in 1795 with six prefixes. The other dates relate to recognition by a resolution of the CGPM. The 1948 recognition of the micron by the CGPM was abrogated in 1967.

References

^ YourDictionary.com, tera-, Retrieved on 2007-06-05.

Tera-

References

See also