fifty · number /ˈfɪf.ti/
fifty
A2 the number 50
Dictionary examples:
forty, fifty, sixty
They were travelling at fifty miles an hour.
Learner example:
There were fifty guests at my party. (Key English Test; A2; Russian)
(be) in your fifties
B2 to be aged between 50 and 59
Dictionary example:
He retired when he was still in his fifties.
Learner example:
Despite being in my fifties I am healthy and in good shape. (First Certificate in English; B2; Polish)
the fifties
B2 the years from 1950-1959
Dictionary example:
Many new towns were built in the fifties.
Learner example:
I love bands from the fifties, sixties, seventies... and most of the radio stations seem to forget that the music has a history and it is always nice to remember past songs, because a good song will always be a good song. (First Certificate in English; B2; Spanish)