**De*nom"i*na`tor** (?), n. [Cf. F. *d'enominateur*.]

**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.
*Sir W. Raleigh.*

**2.** Arith.

That number placed below the line in vulgar fractions which shows into how many parts the integer or unit is divided.

⇒ Thus, in denominator, showing that the integer is divided into five parts; and the numerator, 3, shows how many parts are taken.

**3.** Alg.

That part of any expression under a fractional form which is situated below the horizontal line signifying division.

⇒ 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. )*

© Webster 1913.