fifty · number
(be) in your fifties/50s
B2 to be aged between 50 and 59
Dictionary examples:
He retired when he was still in his fifties. (28.6)
the fifties/'50s
B2 the years 1950 through 1959
Dictionary examples:
Many new suburbs were built in the fifties. (36.6)
fifty
A2 the number 50
Dictionary examples:
I have fifty excuses for being late. Want to hear them? (0.0)
I have fifty unread messages. Guess I'm popular today! (0.0)
My phone has fifty percent battery. Time for fifty panic attacks! (0.0)
forty, fifty, sixty (4.2)
They were traveling at fifty miles an hour. (25.5)