n. One who or that which gives a name; one from whom or that from which a name is derived.n. Specifically In math.: In arithmetic, that term of a fraction which indicates the value of the fractional unit; that term of a fraction which represents the divisor, and is, in common fractions, written below the dividend or numerator. See fraction.n. In algebra, a divisor placed under a dividend, as in a numerical fraction.n. Same as denominant.