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

Deydey 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

The 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

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

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

Synonyms

• big
• consequential
• earth-shattering
• earthshaking
• eventful
• historic
• important
• major
• material
• meaningful
• monumental
• much
• significant
• substantial
• tectonic
• weighty

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

Over the course of U.S. history, presidential rematches have signaled momentous political upheavals by revealing instabilities in the electoral system and exposing tensions in the coalitions of the major parties. —TIME, 4 Apr. 2024

The Star spoke to Jackson County voters this week ahead of Tuesday’s momentous vote. —Kendrick Calfee, Kansas City Star, 30 Mar. 2024

The March 10 Oscars at the Dolby Theatre in Los Angeles unfolded against the backdrop of wars in Gaza and Ukraine, and with a potentially momentous U.S. election on the horizon. —Jake Coyle, The Christian Science Monitor, 11 Mar. 2024

Judith West narrates this superb biography in a methodical manner that takes getting used to, but eventually her voice’s clarity and steady pace strike the listener as appropriate to relaying the myriad details of this courageous, politically momentous life. —Katherine A. Powers, Washington Post, 9 Mar. 2024

The date, 1987, was on the eve of some of the most momentous changes in world history. —Philip Kennicott, Washington Post, 25 Mar. 2024

After a year in London, where Keen’s performance garnered an Olivier Award, the production arrives stateside, just in time for our own momentous election. —The New Yorker, 22 Mar. 2024

Ahead of her momentous evening, Legadoé knew that her dress needed to be from a designer of color. —Kerane Marcellus, Essence, 15 Mar. 2024

Wars are raging, populism is growing, and momentous elections are looming at home and abroad, but luxury’s response is mostly to apply the rules of disengagement. —Laird Borrelli-Persson, Vogue, 12 Mar. 2024

Word History

First Known Use

1631, in the meaning defined above

Kids Definition

momentous

adjective

mo·​men·​tous mō-ˈment-əs 

: very important

a momentous decision

momentously adverb