View source for Mega-

{{Short description|Metric prefix}}
{{Other uses|Mega (disambiguation)}}
{{Wiktionary|mega-}}
'''Mega''' is a [[metric prefix|unit prefix]] in [[metric system]]s of units denoting a factor of one million (10<sup>6</sup> or [[1000000 (number)|{{gaps|1|000|000}}]]). It has the unit symbol '''M'''. It was confirmed for use in the [[International System of Units]] (SI) in 1960. ''Mega'' comes from {{langx|grc|μέγας|mégas|great}}.<ref>{{Cite web|url=http://www.oed.com/view/Entry/115861|title=Oxford English Dictionary (OED Online)|date=June 2001|website=www.oed.com|publisher=Oxford University Press|language=en|access-date=2017-09-18|quote=Origin: A borrowing from Greek. Etymon: Greek μεγα-. ... Forming scientific and technical terms with the sense 'very large', 'comparatively large', or (esp. in Pathol.) 'abnormally large', often having correlatives beginning micro-, and sometimes also synonyms beginning macro-.|url-access=subscription |edition=3rd}}</ref>
==Common examples of usage==
* [[Megapixel]]: 1 million [[pixel]]s in a digital camera
* One megatonne of [[TNT equivalent]] amounts to approx. 4 [[petajoule]]s and is the approximate energy released on igniting one million tonnes of TNT. The unit is often used in measuring the explosive power of [[nuclear weapon]]s.
* [[Megahertz]]: frequency of [[electromagnetic radiation]] for radio and television broadcasting, [[GSM]], etc. 1&nbsp;MHz = 1,000,000&nbsp;[[Hertz|Hz]].
* [[Megabyte]]: unit of information equal to one million bytes (SI standard).
* [[Megawatt]]: equal to one million watts of power.  It is commonly used to measure the output of [[power plant]]s, as well as the power consumption of [[electric locomotive]]s, [[data center]]s, and other entities that heavily consume electricity.
* Megadeath: (or megacorpse) is one million human deaths, usually used in reference to projected number of deaths from a [[nuclear explosion]]. The term was used by scientists and thinkers who strategized likely outcomes of [[all-out nuclear warfare]].
==Exponentiation==
When units occur in [[exponentiation]], such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.
* 1&nbsp;Mm<sup>2</sup> means one square [[megametre]] or the size of a [[Square (geometry)|square]] of {{gaps|1|000|000|m}} by {{gaps|1|000|000|m}} or {{gaps|10<sup>12</sup>|m<sup>2</sup>}}, and not {{gaps|1|000|000|[[square metre]]s}} (10<sup>6</sup>&nbsp;m<sup>2</sup>).
* 1&nbsp;Mm<sup>3</sup> means one cubic [[megametre]] or the size of a [[cube]] of {{gaps|1|000|000|m}} by {{gaps|1|000|000|m}} by {{gaps|1|000|000|m}} or 10<sup>18</sup>&nbsp;m<sup>3</sup>, and not {{gaps|1|000|000|[[cubic metre]]s}} (10<sup>6</sup>&nbsp;m<sup>3</sup>)
==Computing==
In some fields of [[computing]], ''mega'' may sometimes denote {{gaps|1|048|576}} (2<sup>20</sup>) information units, for example, a megabyte, a megaword, but denotes {{gaps|1|000|000}} (10<sup>6</sup>) units of other quantities, for example, transfer rates: {{gaps|1|megabit/s}} = {{gaps|1|000|000|[[bit/s]]}}.
In the case of [[Floppy_disk#3%C2%BD-inch_disk|3½-inch floppy disks]], sizes were given in megabytes of 1000KB or {{gaps|1|024|000}} bits.<ref>{{cite web |title=Megabyte |url=https://mathworld.wolfram.com/Megabyte.html |website=Wolfram MathWorld |access-date=17 June 2024}}</ref>
The prefix ''[[mebi-]]'' has been suggested as a prefix for 2<sup>20</sup> to avoid ambiguity.
{{SI prefixes (infobox)}}
==See also==
* [[Binary prefix]]
* [[Mebibyte]]
* [[Order of magnitude]]
* [[RKM code]]
==References==
{{reflist}}
==External links==
{{wiktionary|mega-}}
*[http://www.bipm.org BIPM website]
[[Category:SI prefixes]]
[[he:תחיליות במערכת היחידות הבינלאומית#מגה]]