mega-
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
mega-
American
especially before a vowel,
meg-.
mega
1
British
/ ˈmɛɡə /
adjective
mega-
2
British
combining form
-
M. denoting 10 6
megawatt
-
(in computer technology) denoting 2 20 (1 048 576)
megabyte
-
large or great
megalith
-
informal great in importance or amount
megastar
mega–
Scientific
-
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.
Usage
What does mega- mean? Mega- is a combining form used like a prefix meaning “large, great, grand, abnormally large.” It is used in many scientific and medical terms. In science, mega- is specifically used as a prefix in units of measure equaling a factor of “one million.” It’s abbreviation is M. So, a megawatt (MW) is one million watts. Mega- comes from the Greek mégas, meaning “large” or “great.”What are variants of mega-?When combined with words or word elements that begin with a vowel, mega- becomes meg-, as in megohm. Mega- is a variant of megalo- and megal-, as in megalomania and megalopsia. Learn more about their specific applications in our Words That Use articles.
Etymology
Origin of mega-
Combining form representing Greek mégas large, great
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Beek looked at the yachts around us, mega- and not.
From Los Angeles Times ● May 9, 2023
The West is in a drought so huge that everyone started throwing the prefix mega- in front of it.
From Salon ● Dec. 29, 2021
In fact, the foundation drew contributions from some who were once Clinton’s most bitter GOP enemies, including Newsmax chief executive Christopher Ruddy and conservative mega- donor Richard Mellon Scaife.
From Washington Post ● Jun. 2, 2015
As high-flying technology stocks crashed and the mega- mergers of the late 1990s faded away, Goldman Sachs’s investment-banking revenue plunged to $2.71 billion in 2003 from $5.37 billion in 2000.
From BusinessWeek ● Jul. 22, 2011
Four of the men were shouting something through mega- phones.
From "Kaffir Boy: An Autobiography" by Mark Mathabane
The figure has since been surpassed, and earlier this month, a record 230 people reached the UK in a so-called "mega dinghy".
From BBC ● Aug. 24, 2026
Skiba pointed to AI companies tapping other sources of capital, including off-balance-sheet deals, mega financing of specific data-center projects and exotic chip-backed deals in the works.
From MarketWatch ● Aug. 19, 2026
“I’m not going to be blind here. We are in the middle of a recovery, and this is one chapter. It’s a mega step, no doubt, but there’s many more mega steps to come.”
From Los Angeles Times ● Aug. 15, 2026
An English court on Friday threw out a challenge against planning permission for a Chinese "mega" embassy in central London, but residents seeking to block the contentious project vowed to fight on.
From Barron's ● Jul. 31, 2026
A mega close-up selfie of Abby and Simon.
From "Leah on the Offbeat" by Becky Albertalli
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
