ninety

1 of 3

noun (1)

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

ninetieth

2 of 3

adjective

nine·​ti·​eth ˈnīntē|ə̇th 

-ti|

1

: being number 90 in a countable series

the ninetieth day

see Table of Numbers

2

: being one of 90 equal parts into which something is divisible

a ninetieth share of the money

ninetieth

3 of 3

noun (2)

"

plural -s

1

: number 90 in a countable series

2

: the quotient of a unit divided by 90 : one of 90 equal parts of something

one ninetieth of the total

Examples of ninety in a Sentence

Noun (1)

During the nineties, he was going to college and working part-time.

Recent Examples on the Web

Noun

In the late nineties, nearly all our revenue was from software license sales and maintenance—large payments up front and a predictable renewal tail. — Amir Wain, Forbes.com, 23 Sep. 2026

His strength in the late nineties was a kind of calm under pressure, and his power in the next decade was translating that swaggering cool for ever-larger stages. — Hua Hsu, New Yorker, 21 Sep. 2026

Spade and Carvey both appeared on the show in the early nineties, with Spade being a cast member from 1990 to 1996 and Carvey from 1986 to 1993. — Virginia Chamlee, PEOPLE, 18 Aug. 2026

Word History

Etymology

Noun (1)

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

Adjective

Middle English nyntithe, from Old English nigontigotha, from nigontig ninety + -otha, -tha -th

First Known Use

Noun (1)

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