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

That would be boxer Vinny Paz or Vinny Pazienza, a tough fighter out of Rhode Island who in the eighties and nineties fought his way to the top of the fight game, earning two championship titles. —Peter Lucas, Boston Herald, 22 Dec. 2025

Steele contrasts two designers of the nineties and two-thousands, John Galliano and Alexander McQueen, by looking at their differing relationships to the female form. —Leslie Jamison, New Yorker, 22 Dec. 2025

In the late nineties, North Lake was a juvenile detention facility. —Meg Anderson, NPR, 18 Dec. 2025

This was the late nineties and the second book in the series had just published or was soon publishing. —Literary Hub, 18 Dec. 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