six·ty 
/ˈsɪksti/ noun
plural six·ties /ˈsɪksti/ noun 1 [count] : the number 60 2 sixties [plural] a : the numbers ranging from 60 to 69
b : a set of years ending in digits ranging from 60 to 69
▪ She likes music from the sixties. [=from 1960 to 1969] ▪ He retired when he was in his sixties.
b : a set of years ending in digits ranging from 60 to 69
▪ She likes music from the sixties. [=from 1960 to 1969] ▪ He retired when he was in his sixties.
— six·ti·eth /ˈsɪkstijəθ/ noun, plural six·ti·eths [count]
▪ one sixtieth of the total
/ˈsɪkstijəθ/ noun, plural six·ti·eths [count] ▪ one sixtieth of the total
— sixtieth adjective
▪ his sixtieth birthday
▪ his sixtieth birthday
— sixty adjective
▪ sixty books
▪ sixty books
— sixty pronoun
▪ Sixty (of them) arrived this morning.
▪ Sixty (of them) arrived this morning.
