Synonyms

mega-

American

especially before a vowel, meg-.

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

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

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

"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

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.

With U.S. stocks stuck in their worst rut since the summer, Treasury bonds in a slump, gold testing $5,000 for the first time on record, and geopolitical risks dominating, the stakes couldn’t be higher for the first round of mega tech earnings coming up next week.

From Barron's

Police chiefs have been calling for the creation of 12 "mega forces" to save money and boost crime-fighting efforts.

From BBC

But how big is the new "mega embassy", as it is often called in the UK media?

From Barron's

Buying Glencore would also give its suitor “pure, unadulterated scale in a world dominated by passive investing and mega caps,” McKay says.

From The Wall Street Journal

After the New York Times ran a headline this past week about the wave of “mega” IPOs expected this year, local real-estate agent Rohin Dhar posted on X: “May I humbly suggest you buy your house in San Francisco before this.”

From The Wall Street Journal

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023