- variant of megalo- (megalith); also the initial element in units of measure that are equal to one million of the units denoted by the base word (megahertz). Symbol: M
- denoting 10 6megawatt Symbol: M
- (in computer technology) denoting 2 20 (1 048 576)megabyte
- large or greatmegalith
- informal great in importance or amountmegastar
before vowels meg-, word-forming element often meaning “large, great,” but in precise scientific language “one million” (megaton, megawatt, etc.), from Greek megas “great, large, vast, big, high, tall; mighty, important” (fem. megale), from PIE *meg- “great” (cf. Latin magnus, Old English micel; see mickle). Mega began to be used alone as an adjective by 1982. High-speed computer stores 2.5 megabits [headline in “Electronics” magazine, Oct. 1, 1957] pref.
- One million (106):megahertz.
- A prefix that means:
- Large, as in megadose, a large dose.
- One million, as in megahertz, one million hertz.
- 220 (that is, 1,048,576), which is the power of 2 closest to a million, as in megabyte.