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

In the early nineties, Orlik signed the lease on the apartment in Kensington. —Sam Knight, New Yorker, 17 June 2025

To give you a sense of the Newton, Mass. of my nineties youth: during my senior year of high school, a mild controversy developed over at the middle school regarding a bulletin board dedicated to significant LGBT people throughout history. —Lucas Schaefer june 13, Literary Hub, 13 June 2025

The over-all effect is like watching a movie that’s supposed to be set in the nineties and spotting a Tesla in the background. —Tyler Foggatt, New Yorker, 8 June 2025

The Bobby Prince stuff for the series in the nineties is iconic. —Joshua Lamb, Forbes.com, 6 June 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