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

Next to a dormant pumpkin farm, the factory, which had once made tubing for hoses, had burned in the nineties; all that remained were four dilapidated and grafittied walls. —Megan Cummins august 5, Literary Hub, 5 Aug. 2025

Growing up in the nineties and early aughts, my peers dressed nearly the same: in preppy pale-hued outfits, linen and seersucker among their wardrobe staples. —Alexis Okeowo, Vogue, 5 Aug. 2025

Then came Eleven Madison Park in the late nineties, which marked a further push into high-end dining and earned three Michelin stars and global recognition. —Martina Di Licosa, Forbes.com, 26 July 2025

Seventeen states had their warmest year on record in 2024, and the past five years have seen the average number of heat waves across the U.S. increase to more than six a year, up from four in the nineties and fewer than three in the seventies. —Melanie Haiken, Outside Online, 23 July 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