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
Their capability of rebooting for another momentous chapter largely hinges on this dynamic repeating itself.
—Kansas City Star, 17 Apr. 2026
Rodrigo has yet to drop tour dates behind GSIL, which will follow her momentous Guts World Tour that wrapped in August 2025 (the double LP Live at Glastonbury showcased her incredible year touring the festival circuit).
—Angie Martoccio, Rolling Stone, 17 Apr. 2026
Dech’s first month on the job has been momentous, seeing the opening of the Monon Corridor service and now the groundbreaking for the downtown Hammond station.
—Doug Ross, Chicago Tribune, 17 Apr. 2026
The trip had momentous political significance.
—Rebecca Mead, New Yorker, 17 Apr. 2026
See All Example Sentences for momentous
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Kansas City Star, 17 Apr. 2026
Rodrigo has yet to drop tour dates behind GSIL, which will follow her momentous Guts World Tour that wrapped in August 2025 (the double LP Live at Glastonbury showcased her incredible year touring the festival circuit).
—Angie Martoccio, Rolling Stone, 17 Apr. 2026
Dech’s first month on the job has been momentous, seeing the opening of the Monon Corridor service and now the groundbreaking for the downtown Hammond station.
—Doug Ross, Chicago Tribune, 17 Apr. 2026
The trip had momentous political significance.
—Rebecca Mead, New Yorker, 17 Apr. 2026
See All Example Sentences for momentous
Cite this Entry
“Momentous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/momentous. Accessed 22 Apr. 2026.
Copy CitationKids Definition
momentous
adjective
mo·men·tous
mō-ˈment-əs
: very important
a momentous decision
momentously
adverb
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