(informal) Of about sixty years of age.

(UK, US) An often nostalgic name for the 1960s.

plural of sixth form

By a multiple of sixty; by sixty times as much or as many.

By a factor of sixty.

plural of sixty-fourmo

plural of sixty-eighth

plural of minor sixth

plural of major sixth

(music) A musical interval of the Western twelve-semitone system consisting of eight semitones and spanning six degrees of the diatonic scale. It is one semitone narrower than a major sixth and enharmonically equivalent to an augmented fifth.