momentous
adjective
mo·men·tous
mō-ˈmen-təs 
mə-
: having great or lasting importance : consequential, significant
a momentous decision
a momentous event/occasion
The Senate begins a momentous debate on health care today …—
The New York Times
The New York TimesDeydey usually talked about his travels, the places he'd seen and the people, the close calls and momentous encounters with animals, weather, other Anishinabeg, and best of all, ghosts.—Louise Erdrich
Louise ErdrichThe late nineteenth century was strewn with inventions. Many were momentous, but few affected men and women more closely than the bicycle and its motorized offspring: motorcycle, motor-car and aeroplane.—Eugen Weber
Eugen Weber
momentously
adverb
a momentously important decision
… a … twist that is executed differently from the comic book story, but is just as dramatically and momentously presented.
—The Philippines Daily Inquirer
The Philippines Daily Inquirer
momentousness
noun
But other East Europeans had little time to marvel at the momentousness of the moment. Just one day after the fall of the [Berlin] Wall, Bulgaria's dour leader of 35 years, Todor Zhivkov, was ousted.
—Stephen E. Deane
Stephen E. Deane
Examples of momentous in a Sentence
My college graduation was a momentous day in my life.
a momentous occasion that will go down in the history books
Recent Examples on the Web
It’s been a momentous year for Augustinus Bader.
—Adam Hurly, Robb Report, 18 Sep. 2025
Default windows open at a size of 120 columns and 30 rows, up from the previous 80 columns and 24 rows (those numbers were derived from the display resolutions of 1970s-era computer terminals, so the change is quietly momentous).
—ArsTechnica, 15 Sep. 2025
The installation of the cross on the Jesus tower, by establishing the church’s signature profile, will be a momentous event in the basilica’s history.
—D. T. Max, New Yorker, 15 Sep. 2025
The Panthers’ momentous win over the Cards last year came right after the team’s letdown loss against the Dallas Cowboys at home — one that came thanks to a four-turnover game by Young, too.
—Alex Zietlow, Charlotte Observer, 11 Sep. 2025
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Adam Hurly, Robb Report, 18 Sep. 2025
Default windows open at a size of 120 columns and 30 rows, up from the previous 80 columns and 24 rows (those numbers were derived from the display resolutions of 1970s-era computer terminals, so the change is quietly momentous).
—ArsTechnica, 15 Sep. 2025
The installation of the cross on the Jesus tower, by establishing the church’s signature profile, will be a momentous event in the basilica’s history.
—D. T. Max, New Yorker, 15 Sep. 2025
The Panthers’ momentous win over the Cards last year came right after the team’s letdown loss against the Dallas Cowboys at home — one that came thanks to a four-turnover game by Young, too.
—Alex Zietlow, Charlotte Observer, 11 Sep. 2025
See All Example Sentences for momentous
Cite this Entry
“Momentous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/momentous. Accessed 20 Sep. 2025.
Copy CitationKids Definition
momentous
adjective
mo·men·tous
mō-ˈment-əs
: very important
a momentous decision
momentously
adverb
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