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.

---

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

---

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

That date can be set no sooner than ninety days from the date of Paxton’s request.

From Salon ● Jun. 29, 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

It would’ve taken me till I was ninety to get the diamond willow posts and wire out to the field if I hadn’t.

From "Hattie Big Sky" by Kirby Larson

He was still working well into his nineties - last year, after the death of Pope Francis, Willey reflected on how the Vatican had changed under the late pontiff.

From BBC ● Jul. 12, 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 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 may know her as the mom from Stranger Things, but in the nineties, Winona was the "it" girl.

From "Americanized" by Sara Saedi