Mega-

Look up mega- in Wiktionary, the free dictionary.

mega (symbol M) is an SI prefix in the SI system of units denoting a factor of 10⁶, 1,000,000 (one million).

For example, 1 MW (megawatt) = 1,000,000 watts = 1,000 kilowatts.

Confirmed in 1960, it comes from the Greek μέγας, meaning great.^[1]

Contents 1 Other common examples of usage 2 Exponentiation 3 Computing 4 See also 5 References 6 External links

Other common examples of usage

• megapixel - 1 million pixels in a digital camera
• one megaton [of TNT] (a unit often used in measuring the explosive power of nuclear weapons) is 1,000,000 tons of TNT.
• megahertz—frequency of electromagnetic radiation for radio and television broadcasting, GSM, etc. 1 MHz = 1,000,000 Hz.
• megadeath - one million deaths caused by nuclear war

Exponentiation

When units occur in exponentiation, such as in square and cubic forms, any size prefix is considered part of the unit, and thus included in the exponentiation.

• 1 Mm² means one square megametre or the size of a square of 1,000,000 m by 1,000,000 m or 10¹² m², and not 1,000,000 square metres (10⁶ m²).
• 1 Mm³ means one cubic megametre or the size of a cube of 1,000,000 m by 1,000,000 m by 1,000,000 m or 10¹⁸ m³, and not 1,000,000 cubic metres (10⁶ m³)

Computing

In computing, mega can sometimes denote 1,048,576 (2²⁰) of information units (example: a megabyte, a megaword), but can denote 1,000,000 (10⁶) of other quantities, for example, transfer rates: 1 megabit/s = 1,000,000 bit/s.

The prefix mebi has been suggested as a prefix for 2²⁰ to avoid ambiguity.

SI prefixes

1000m	10n	Prefix	Symbol	Since[1]	Short scale	Long scale	Decimal
10008	1024	yotta	Y	1991	Septillion	Quadrillion	1000000000000000000000000
10007	1021	zetta	Z	1991	Sextillion	Trilliard	1000000000000000000000
10006	1018	exa	E	1975	Quintillion	Trillion	1000000000000000000
10005	1015	peta	P	1975	Quadrillion	Billiard	1000000000000000
10004	1012	tera	T	1960	Trillion	Billion	1000000000000
10003	109	giga	G	1960	Billion	Milliard	1000000000
10002	106	mega	M	1960	Million		1 000 000
10001	103	kilo	k	1795	Thousand		1000
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		0.000001
1000−3	10−9	nano	n	1960	Billionth	Milliardth	0.000000001
1000−4	10−12	pico	p	1960	Trillionth	Billionth	0.000000000001
1000−5	10−15	femto	f	1964	Quadrillionth	Billiardth	0.000000000000001
1000−6	10−18	atto	a	1964	Quintillionth	Trillionth	0.000000000000000001
1000−7	10−21	zepto	z	1991	Sextillionth	Trilliardth	0.000000000000000000001
1000−8	10−24	yocto	y	1991	Septillionth	Quadrillionth	0.000000000000000000000001
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.

See also

• SI prefix
• Binary prefix
• Mebibyte
• Orders of magnitude

References

1. ^ "[http://dictionary.oed.com/cgi/entry/00304790 mega-]". Oxford English Dictionary. Oxford University Press. 2nd ed. 1989.

External links

• BIPM website

sex

stock | retire | vm
Why are we here?
All text is available under the terms of the GNU Free Documentation License
This page is cache of Wikipedia. History