forty

noun

for·​ty ˈfȯr-tē 

plural forties

1

: a number equal to four times 10 see Table of Numbers

2

forties plural : the numbers 40 to 49

specifically : the years 40 to 49 in a lifetime or century

3

: the third point scored by a side in a game of tennis

4

or 40 US, informal : a forty-ounce bottle or other container of an alcoholic beverage (such as beer or malt liquor)

Kelvin finished his forty in seven or eight long gulps. Tossed the bottle in the median carpeted with brown grass.

—Dave Byrne

… smoking weed and drinking 40s while her kids run loose.

—Jim Schutze

fortieth

ˈfȯr-tē-əth 

adjective or noun

forty adjective

forty pronoun, plural in construction

fortyish

ˈfȯr-tē-ish 

adjective

The Spelling of Forty: Usage Guide

Four is spelled with a u, as is fourteen. Forty, however, has no u, and neither does its close relation fortieth. There is no explanation for this inconsistency. In centuries past fourty was one of many spellings English users employed, but it had lost favor for reasons unknown by the end of the 18th century.

Examples of forty in a Sentence

The temperature outside is in the high forties.

She is in her forties.

Recent Examples on the Web

There are photographs that attest to the latter, one from his early twenties, another from later, in his forties, a full-on adult with the weight of responsibility visible in the lines of his forehead. —Literary Hub, 4 Nov. 2025

Monsignor Angelo Cioffi was the priest who spearheaded the campaign to construct Regina Pacis back in the forties, with generous assistance from Joe Profaci. —Susan Mulcahy, New Yorker, 3 Nov. 2025

This makes sense; workers typically see their earnings peak around their mid to late forties, according to ADP research. —Kamaron McNair, CNBC, 27 Oct. 2025

In a hotel room, a melancholy sabra in his forties muses over the paradoxes of the historical destiny of the Jews. —Susan Sontag, Vogue, 26 Oct. 2025

Word History

Etymology

Middle English fourty, adjective, from Old English fēowertig, from fēowertig group of 40, from fēower four + -tig group of 10; akin to Old English tīen ten

First Known Use

before the 12th century, in the meaning defined at sense 1

Phrases Containing forty

• forty-five
• forty-niner
• forty winks

Rhymes for forty

• corti
• rorty
• shorty
• sortie
• sporty
• warty
• pianoforte

Kids Definition

forty

noun

for·​ty ˈfȯrt-ē 

plural forties

: a number equal to four times 10 see number

fortieth

-ē-əth 

adjective or noun

forty adjective or pronoun

fortyish

-ē-ish 

adjective