Denominator /(?)/

De·nom·i·na·tor

Denominator

n.
  1. One who, or that which, gives a name; origin or source of a name.
    This opinion that Aram . . . was the father and denomination of the Syrians in general.
  2. That number placed below the line in common fractions which shows into how many parts the integer or unit is divided. (Arith.)
  3. That part of any expression under a fractional form which is situated below the horizontal line signifying division. (Alg.)

Phrases & Compounds
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..