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

Her parents had come to the United States from Durango, Mexico, in the early nineties. —Ruby Cramer, New Yorker, 12 Mar. 2026

Jason Piazza, who first came on staff in the late nineties, took over the business in 2004, and his mission has been to maintain the flavors and the vibe that make Hugo’s such an important part of this college town. —Chelsea Brasted, Southern Living, 12 Mar. 2026

Into his nineties, Robinson was scattering bulbs from his wheelchair. —Amy Waldman, Travel + Leisure, 9 Mar. 2026

By the eighties and nineties, eruptions were extreme, sometimes lasting over 90 minutes. —Madison Dapcevich, Outside, 4 Mar. 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