a cardinal number, ten times six.

a symbol for this number, as 60 or LX.

a set of this many persons or things.

sixties, the numbers, years, degrees, or the like, from 60 through 69, as in referring to numbered streets, indicating the years of a lifetime or of a century, or noting degrees of temperature

Her grandfather is in his late sixties. The temperature is in the low sixties.

amounting to 60 in number. ?

like sixty, Informal . with great speed, ease, energy

or zest

Everyone was working like sixty to finish up before the holidays.