WORD ORIGIN 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). : M Symbol
, especially before a vowel meg-. Origin of mega-
combining form representing
Greek mégas large, great
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for mega- combining form denoting 10 6 megawatt Symbol: M (in computer technology) denoting 2 20 (1 048 576) megabyte large or great megalith informal great in importance or amount megastar Word Origin for mega-
megas huge, powerful
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for mega-
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]
Online Etymology Dictionary, © 2010 Douglas Harper
pref. Large: megacephaly. One million (10 6): megahertz.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
A prefix that means: Large, as in megadose, a large dose. One million, as in megahertz, one million hertz. 2 20 (that is, 1,048,576), which is the power of 2 closest to a million, as in megabyte.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.