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

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

Since the nineties alone, nearly three hundred million acres of agricultural land across Europe have been abandoned. — M. R. O’Connor, New Yorker, 1 Aug. 2026

Pathbreaking Italian American artist, choreographer, and dancer Simone Forti has died at the age of ninety-one. — News Desk, Artforum, 29 July 2026

These useful totes are reminiscent of nineties-era swim bags. — Rebecca Jones, Southern Living, 27 June 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