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Mega is a unit prefix in metric systems of units denoting a factor of one million (106 or 1000000). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. Mega comes from the Greek μέγας megas, meaning "great".
Common examples of usageEdit
- Megapixel: 1 million pixels in a digital camera
- One megatonne of TNT equivalent amounts to approx. 4 petajoules 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 weapons.
- Megahertz: frequency of electromagnetic radiation for radio and television broadcasting, GSM, etc. 1 MHz = 1,000,000 Hz.
- Megabyte: unit of information equal to- depending on definition- either one million bytes (SI standard) or 1048576 bytes (traditional).
- Megawatt: equal to one million watts of power. It is commonly used to measure the output of power plants, as well as the power consumption of electric locomotives, data centers, and other entities that heavily consume electricity.
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.
In some fields of computing, mega may sometimes denote 1,048,576 (220) of information units, for example, a megabyte, a megaword, but denotes 1000000 (106) units of other quantities, for example, transfer rates: 1megabit/s = 1000000bit/s. The prefix mebi- has been suggested as a prefix for 220 to avoid ambiguity.
- Prefixes adopted before 1960 already existed before SI. 1873 was the introduction of the CGS system.
- "Oxford English Dictionary (OED Online)". www.oed.com (3rd ed.). Oxford University Press. June 2001. Retrieved 2017-09-18. (Subscription required (help)).
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-.