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

Now in his early nineties, Gregory (My Dinner with André, NYFF19) shows no sign of slowing down, as evidenced by this delightful, enormously moving document of his inextinguishable creative spark. — Jill Goldsmith, Deadline, 11 Aug. 2026

Back in the nineties, both Democrats and Republicans loved to praise the unlikely friendship of the (liberal, feminist) Justice Ruth Bader Ginsburg and the (conservative, originalist) Justice Antonin Scalia. — Margaret Talbot, New Yorker, 10 Aug. 2026

The sudden closures came as temperatures reached into the nineties in the US capital, with excess humidity prompting a heat alert for the city. — News Desk, Artforum, 7 Aug. 2026

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

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