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

“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

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

The meridians are perpendicular to the parallels on the surface of the globe; that is, they meet at right angles, or ninety degrees.

From "Shipwreck at the Bottom of the World" by Jennifer Armstrong

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

"We haven't hit rubbish from the nineties and noughties, so that's going to be extortionate amounts," he said.

From BBC ● Feb. 18, 2026

But elderly people who buck this trend - and who hold on to their good bacteria well through their eighties and nineties - have been shown to live longer, healthier lives.

From BBC ● Jan. 12, 2026

There is “real diversity in health and well-being” for retirees, Hershfield said, noting that some people are sedentary at 65, and others are running marathons into their nineties.

From Los Angeles Times ● Oct. 1, 2024

“You make it sound like the nineties were hell,” I said.

From "Made You Up" by Francesca Zappia