[1] : The Collaborative International Dictionary of English v.0.48

denominator \denom"ina`tor\, n. cf. f. d'enominateur.
   1. one who, or that which, gives a name; origin or source of
      a name.
      1913 webster

            this opinion that aram . . . was the father and
            denomination of the syrians in general. --sir w.
                                                  raleigh.
      1913 webster

   2. arith. that number placed below the line in common
      fractions which shows into how many parts the integer or
      unit is divided.
      1913 webster

   note: thus, in 3/5, 5 is the denominator, showing that the
         integer is divided into five parts; and the numerator,
         3, shows how many parts are taken.
         1913 webster

   3. alg. that part of any expression under a fractional form
      which is situated below the horizontal line signifying
      division.
      1913 webster

   note: in this sense, the denominator is not necessarily a
         number, but may be any expression, either positive or
         negative, real or imaginary. --davies  peck math.
         dict.
         1913 webster

   common denominator a number which can divide either of two
      or more other numbers without leaving a remainder in any
      of the divisions; as, 2 and 4 are common denominators of
      12 and 28..

   greatest common denominator the largest common
      denominator of two or more numbers; as, 9 is the greatest
      common denominator of 18 and 27..
      pjc
see also:
common denominator greatest common denominator common denominator 

[2] : WordNet (r) 2.0

denominator
     n : the divisor of a fraction

Denominator >> D Words
Denominator, definition of term: Denominator
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