momentous

American

[moh-men-tuhs] / moʊˈmɛn təs /

adjective

of great or far-reaching importance or consequence.

a momentous day.

Synonyms:

serious, crucial, critical, vital

Antonyms:

trifling, trivial

momentous British

/ məʊˈmɛntəs /

adjective

of great significance

"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

Related Words

See heavy.

Other Word Forms

momentously adverb
momentousness noun
unmomentous adjective
unmomentously adverb
unmomentousness noun

Etymology

Origin of momentous

First recorded in 1645–55; moment + -ous

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.

These momentous gains contributed to an increase in market value that helped them secure their spots in the S&P 500.

From Barron's

Bellamy scored the winning goal when Wales last faced Italy in Cardiff, a momentous occasion at a sold-out Millennium Stadium.

From BBC

These momentous shifts partly explain how the U.S. economy easily withstood a surge in oil prices following the Russian invasion of Ukraine in 2022.

From MarketWatch

Lamarck invented the term “invertebrates” and, the author notes, his humble new field of study helped steer him toward his “momentous new theory of the history of life.”

From The Wall Street Journal

Going overboard on the momentous nature of this contest is not a smart play.

From BBC

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