forty

American  

[fawr-tee] / ˈfɔr ti /

noun

forties plural

1. a cardinal number, ten times four.

2. a symbol for this number, as 40 or XL or XXXX.

3. a set of this many persons or things.

4. forties, the numbers, years, degrees, or the like, from 40 through 49, as in referring to numbered streets, indicating the years of a lifetime or of a century, or degrees of temperature.

   His office is in the West Forties. Her parents are in their forties. The temperature will be in the forties.

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adjective

1. amounting to 40 in number.

forty British  

/ ˈfɔːtɪ /

noun

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

2. a numeral, 40, XL, etc, representing this number

3. something representing, represented by, or consisting of 40 units

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determiner

1. 1. amounting to forty

      forty thieves

   2. ( as pronoun )

      there were forty in the herd

Other Word Forms

Noun Inflected Forms

• forties
  plural

Etymology

Origin of forty

before 950; Middle English fourti, Old English fēowertig (cognate with Old Frisian fiuwertich, Old High German fiorzug, German vierzig ). See four, -ty ¹

Explanation

Whether you call it 40 or XL, you're talking about forty: the number between thirty-nine and forty-one. If you’ve ever seen the Roman numeral XL, that means forty, since X equals ten, L equals 50 and if you put the X before the L it means L minus X or 50 minus 10 — which is 40. This number comes up in the Bible a lot, especially when the earth is said to have been flooded for forty days and forty nights. Most people are not that thrilled to turn 40 years old: it means they're middle-aged.

Example Sentences

See Examples For:

forty forties

In our town, we’re told in the new LA28 announcement of the Cultural Olympiad: “It’s been forty years. Los Angeles is ready to do it again.”

From Los Angeles Times ● May 11, 2026

Birol told Australian media that at least forty energy assets across the region had been "severely or very severely damaged" in the conflict.

From Barron's ● Mar. 23, 2026

“By the time the Scramble for Africa was over,” Martin Meredith tells us, the vagaries of geopolitical geometry had amalgamated “some 10,000 African polities . . . into forty European colonies and protectorates.”

From The Wall Street Journal ● Mar. 17, 2026

There was no reason I couldn’t close the laptop for forty minutes.

From Salon ● Feb. 19, 2026

They settle down on top of my booties in the bootie sack and that night it gets forty or fifty below and the cans of soda freeze and burst.

From "Woodsong" by Gary Paulsen

"I had gone to bed a bit late, but the air-raid sirens woke me up, leaving me feeling anxious," said Nawal Saad, a Bahraini civil servant in her forties.

From Barron's ● Jul. 8, 2026

"We're not cutting the trees. We just pick up whatever wood's already on the ground to use for the fire," said Nafisa, a woman in her forties navigating the dry grasslands.

From Barron's ● Feb. 19, 2026

Even though McDaniels is still in his forties, he has been working in the same system long enough that he seems to know instantly how to address any situation.

From The Wall Street Journal ● Feb. 4, 2026

Elsewhere, a woman in her forties is reported to have died in Valencia, though there is no clear consensus in Spanish media on the cause of her death.

From BBC ● Apr. 30, 2025

In the comer of a parking lot, among the sumptuous boutiques, they’ve reconstructed a forties diner. 4-D’s Diner, it’s called.

From "Cat's Eye" by Margaret Atwood