ninety

noun

nine·​ty ˈnīn-tē 

plural nineties

1

: a number equal to nine times 10 see Table of Numbers

2

nineties plural : the numbers 90 to 99

specifically : the years 90 to 99 in a lifetime or century

She's in her nineties.

ninetieth

ˈnīn-tē-əth 

adjective or noun

ninety adjective

ninety pronoun, plural in construction

Examples of ninety in a Sentence

During the nineties, he was going to college and working part-time.

Recent Examples on the Web

But until the early nineties, breath-holding wasn’t a sport but a means to a living. —Sean Williams, Outside, 27 Oct. 2025

For those living under a rock, the nineties are experiencing a renaissance, even with people too young to have experienced them (at least sentiently) the first time around. —Nora Dahlia, PEOPLE, 25 Oct. 2025

Apple computers have come with text-editing software since the original Mac was released, in 1984; the current iteration of the program launched in the mid-nineties and has survived relatively unchanged. —Kyle Chayka, New Yorker, 22 Oct. 2025

Dominique Trenier, [D’Angelo’s former manager], was one of my friends, [and] got in trouble somehow [one day in the nineties]. —Andre Gee, Rolling Stone, 16 Oct. 2025

Word History

Etymology

Middle English ninety, adjective, from Old English nigontig, short for hundnigontig, from hundnigontig, noun, group of 90, from hund-, literally, hundred + nigon nine + -tig group of 10; akin to Old English tīen ten

First Known Use

before the 12th century, in the meaning defined at sense 1

Phrases Containing ninety

• ninety-nine times out of a hundred
• ninety/ninety-nine percent of the time

Kids Definition

ninety

noun

nine·​ty ˈnīnt-ē 

plural nineties

1

: a number equal to nine times 10 see number

2

plural : the numbers 90 to 99 and specifically the years 90 to 99 in a lifetime or century

ninetieth

-ē-əth 

adjective or noun

ninety adjective or pronoun