momentous
Americanadjective
adjective
Synonym Usage
See heavy.
Other Word Forms
Etymology
Origin of momentous
Explanation
Momentous describes an important event or moment in time. It is used for a time of great consequence or for a major accomplishment, and is almost always reserved for good things. When a moment is so great you know you'll never forget it, you have just experienced something momentous. It can be personal — perhaps the day you were named prom queen; or something historic — like the day Elizabeth was named Queen of England. Momentous and momentary share the root word moment but momentary describes just one fleeting moment in time. A momentary occurrence can certainly be momentous, but it's not always the case.
Vocabulary lists containing momentous
The SAT: Words to Capture Tone, List 3
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The New SAT: Words to Capture Tone
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100 SAT Words Beginning with "M"
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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.
This raises a momentous question: If diagnosed with a terminal illness, how can you weigh the decision in a calm, unhurried, fully informed manner?
From MarketWatch ● Jul. 20, 2026
Andy Tobias, whose father Lieutenant Colonel John Tobias MBE, said it was a "hugely momentous day"
From BBC ● Jul. 14, 2026
Meanwhile, the development of autonomous systems guided by artificial intelligence heralds an even more momentous turn.
From The Wall Street Journal ● Jul. 7, 2026
This week, Emily Bazelon, David Plotz, and guest host Ruth Marcus discuss this week’s momentous Supreme Court rulings.
From Slate ● Jul. 3, 2026
Part of me felt like something momentous was about to happen.
From "Miss Peregrine's Home for Peculiar Children" by Ransom Riggs
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.
