ninety

[ nahyn-tee ]

noun

, plural nine·ties.

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

/ 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

Word History and Origins

Origin of ninety¹

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

Word History and Origins

Origin of ninety¹

Old English nigontig

Example Sentences

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

During the nineties, Fagan said the think tank grew to work more closely with House Republicans, offering harsh criticism of former President George W. Bush's immigration plan.

From Salon

She will finish her fourth degree, her third with The Open University, when she is in her nineties.

From BBC

With bolt cutters for the chain on the fence and a lockpick for the main door, he was inside in less than ninety seconds.

From Literature

The stone, with the rope trailing it, made a small parabola in the air, and the line, as if with a sigh, fell limply into the river only ninety tails away.

From Literature

How Do You Spell 90?

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.