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  • mega-
    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
    mega
    adjective
    extremely good, great, or successful
  • mega–
    mega–
    A prefix that means:
Synonyms

mega-

American  
especially before a vowel, meg-.
  1. 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 1 British  
/ ˈmɛɡə /

adjective

  1. slang extremely good, great, or successful

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

mega- 2 British  

combining form

  1. M. denoting 10 6

    megawatt

  2. (in computer technology) denoting 2 20 (1 048 576)

    megabyte

  3. large or great

    megalith

  4. informal great in importance or amount

    megastar

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

mega– Scientific  
  1. A prefix that means:

  2. Large, as in megadose, a large dose.

  3. One million, as in megahertz, one million hertz.

  4. 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

That is twice the price of a mega vessel built in South Korea or China.

From The Wall Street Journal ● Oct. 12, 2026

But a mega brand like Louis Vuitton sells luxury to the masses.

From The Wall Street Journal ● Oct. 3, 2026

A mega $30 billion bond-financing package to help Paramount Skydance Corp. buy Warner Bros.

From MarketWatch ● Sep. 30, 2026

Last autumn scrum-half Alex Mitchell said he and others had prioritised the togetherness, external and quality of Saints' squad over "mega money" elsewhere when opting to re-sign.

From BBC ● Sep. 16, 2026

Not without a serious, and Seven was talking mega, apology.

From "Witchlings" by Claribel A. Ortega

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