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

He had been involved in dissident circles since his student days, in the nineties. —Jon Lee Anderson, New Yorker, 29 Sep. 2025

The Seinfeld reunion season moved the show back onto the original lot and soundstage where the nineties sitcom was shot. —Thr Staff, HollywoodReporter, 25 Sep. 2025

Alas, this was the mid-nineties, the era of Blockbuster Video ubiquity, and long before the Internet made obtaining obscure movies a one-click ordeal. —Outside, 25 Sep. 2025

The Tommy Jeans division of Tommy Hilfiger was created under Andy’s direction and helped skyrocket the brand to becoming a staple in music videos and album covers, as well as cementing itself as a streetwear powerhouse during the golden age of hip-hop in the late nineties. —Doug Melville, Forbes.com, 10 Sep. 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