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

America’s refusal dates back to the nineteen-nineties; considering this, the current Administration’s actions can be seen only as a shameful continuation of our country’s failure to respect human rights, even on its own soil. —The New Yorker, New Yorker, 4 May 2026

The abbey's hotel closed in the nineties—a casualty of the rise in the popularity of chalet rentals over hotel rooms—but tourism in the valley is going strong. —CBS News, 1 May 2026

One of the South's most iconic appetizers fuses with the nineties' obsession with Tex-Mex to create a twist on this beloved party appetizer. —Jenna Sims, Southern Living, 1 May 2026

In the opening pages, the real-life Japanese writer Yone Noguchi…sets sail, in the eighteen-nineties, for San Francisco. —Literary Hub, 23 Apr. 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