ninety

American  

[nahyn-tee] / ˈnaɪn ti /

noun

• nineties
  plural

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.

Other Word Forms

Noun Inflected Forms

• nineties
  plural

Etymology

Origin of ninety

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

Explanation

Ninety is a number that's ten more than eighty and ten less than a hundred. Ninety is a pretty big number, but there's not much else to say about it. It's one of those numbers like "sixty" or "seventy" that is formed by attaching a number in the range of 1-9 and "ty" to represent values in the tens place starting with that number. And if you were alive during the nineties (the years from 1990-1999), you probably watched a lot of "Seinfeld" and "Friends."

Example Sentences

See Examples For:

ninety nineties

For ninety minutes at least, supporters and critics found themselves watching the same screen, celebrating the same attacks and groaning at the same missed opportunities.

From Barron's ● Jun. 21, 2026

And those improved recommendations come at a much lower cost, he said, sometimes ninety percent less than using the proprietary models favoured by US AI developers.

From BBC ● Jan. 23, 2026

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

From Los Angeles Times ● Sep. 10, 2025

After ninety days, there were four times fewer people in the benralizumab group that failed treatment compared to standard of care with prednisolone.

From Science Daily ● Nov. 27, 2024

Holly reined in the throttle and descended to ninety yards.

From "Artemis Fowl" by Eoin Colfer

He managed the property in the village of Llanddeusant, Anglesey, until he died in his nineties.

From BBC ● Aug. 10, 2026

Afridi was clobbered for a six and a four as Brook raced through the "nervous nineties" in two balls, going from 90 to 100 before raising his bat.

From Barron's ● Feb. 24, 2026

He continued to write opinion pieces into his eighties and nineties, bemoaning the stature of modern-day politicians and the lack of working-class voices in politics.

From BBC ● Feb. 19, 2025

“There had been an earlier project called the Cardiff Bay Opera House, that was in the early nineties, and that didn’t go ahead.”

From BBC ● Dec. 1, 2024

Before Khalil, I planned to cold-shoulder Chris with a sting more powerful than a nineties R&B breakup song.

From "The Hate U Give" by Angie Thomas