The Collaborative International Dictionary of English v.0.48:

Numerator \Nu"mer*a"tor\, n. [L. numerator: cf. F.
   num['e]rateur.]
   1. One who numbers.
      [1913 Webster]

   2. (Math.) The term in a fraction which indicates the number
      of fractional units that are taken.
      [1913 Webster]

   Note: In a vulgar fraction the numerator is written above a
         line; thus, in the fraction 5/9 (five ninths) 5 is the
         numerator; in a decimal fraction it is the number which
         follows the decimal point. See Fraction.
         [1913 Webster] Numeric

WordNet (r) 3.0 (2006):

numerator
    n 1: the dividend of a fraction