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

Now in his early nineties, Gregory (My Dinner with André, NYFF19) shows no sign of slowing down, as evidenced by this delightful, enormously moving document of his inextinguishable creative spark. — Jill Goldsmith, Deadline, 11 Aug. 2026

Back in the nineties, both Democrats and Republicans loved to praise the unlikely friendship of the (liberal, feminist) Justice Ruth Bader Ginsburg and the (conservative, originalist) Justice Antonin Scalia. — Margaret Talbot, New Yorker, 10 Aug. 2026

The sudden closures came as temperatures reached into the nineties in the US capital, with excess humidity prompting a heat alert for the city. — News Desk, Artforum, 7 Aug. 2026

Yavuzer’s Juno Design and Manufacture, based in Güngören, Istanbul, has been building hammams, steam rooms and therapy rooms for hotels internationally since the mid-nineties, including projects like the Merit Starlit in Montenegro. — Lilian Raji, Forbes.com, 1 Aug. 2026

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