Meaning of “forty” - Learner’s Dictionary

forty

us uk /ˈfɔːti/
He looks about forty.The shirt was forty pounds.I've invited forty people to the party.It took about forty minutes in all.Forty years later, he went back to the town.

A2 the number 40

the forties

the years from 1940 to 1949

be in your forties

to be aged between 40 and 49

fortieth

40th written as a word

(Definition of “forty” from the Cambridge Learner’s Dictionary © Cambridge University Press)