a. [ See Nine, and cf. Forty. ] Nine times ten; eighty-nine and one more; as, ninety men. [ 1913 Webster ]
n.; pl. Nineties 1. The sum of nine times ten; the number greater by a unit than eighty-nine; ninety units or objects. [ 1913 Webster ]
2. A symbol representing ninety units, as 90 or xc. [ 1913 Webster ]