资料来源 : Webster's Revised Unabridged Dictionary (1913)

Ninety \Nine"ty\, n.; pl. {Nineties}.
   1. The sum of nine times ten; the number greater by a unit
      than eighty-nine; ninety units or objects.

   2. A symbol representing ninety units, as 90 or xc.

资料来源 : WordNet®

nineties
     n 1: the decade from 1890 to 1899 [syn: {1890s}]
     2: the decade from 1990 to 1999 [syn: {1990s}]
     3: the time of life between 90 and 100 [syn: {mid-nineties}]