ninety

American  

[nahyn-tee] / ˈnaɪn ti /

noun

plural

nineties

1. a cardinal number, ten times nine.

2. a symbol for this number, as 90 or XC.

3. a set of this many persons or things.

4. nineties, the numbers, years, degrees, or the like, from 90 through 99, as in referring to numbered streets, indicating the years of a lifetime or of a century, or degrees of temperature.

   His grandmother is in her nineties.

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adjective

1. amounting to 90 in number.

ninety British  

/ ˈnaɪntɪ /

noun

1. the cardinal number that is the product of ten and nine See also number

2. a numeral, 90, XC, etc, representing this number

3. something represented by, representing, or consisting of 90 units

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determiner

1. 1. amounting to ninety

      ninety times out of a hundred

   2. ( as pronoun )

      at least ninety are thought to be missing

Usage

Spelling tips for 90 The word ninety (90) is hard to spell because it can be hard to remember whether to include the e from nine when combining it with the suffix -ty. How to spell ninety: To spell ninety, you simply combine the base number (nine) with the suffix -ty, which means "multiple of 10." 9 x 10 = 90 or, in writing, nine + -ty = ninety.

Etymology

Origin of ninety

before 1000; Middle English nineti, Old English nigontig. See nine, -ty ¹

Example Sentences

“Seventy to ninety percent of my life throughout those years was with him,” he says.

From Los Angeles Times • Sep. 10, 2025

Dr Runsheng Yin has published over ninety peer-reviewed papers and served as an editor-in-chief for the international journal of Forest Policy and Economics.

From Science Daily • Feb. 26, 2024

In 1968, four years after the nursery study began at Howard, the federal Children’s Bureau released a ninety two-page report of the findings.

From Scientific American • Oct. 26, 2023

England lost by one goal to Spain after a tense ninety minutes and going close by hitting the bar, pushing the eventual champions right up until the final whistle.

From BBC • Aug. 20, 2023

"We got ninety cents and we need as much candy as you can give us," John John explained.

From "Look Both Ways" by Jason Reynolds