Source : Webster's Revised Unabridged Dictionary (1913)

Contralto \Con*tral"to\ (? or ?), a. (Mus.)
   Of or pertaining to a contralto, or to the part in music
   called contralto; as, a contralto voice.

Contralto \Con*tral"to\ (? or ?), n. [It., fr. contra + alto.
   See {Alto}.] (Mus.)
   (a) The part sung by the highest male or lowest female
       voices; the alto or counter tenor.
   (b) the voice or singer performing this part; as, her voice
       is a contralto; she is a contralto.

   Note: The usual range of the contralto voice is from G, below
         middle C, to the C above that; though exceptionally it
         embraces two octaves.

Source : WordNet®

contralto
     adj : of or being the lowest female voice [syn: {alto}]
     n 1: a woman singer having a contralto voice
     2: the lowest female singing voice [syn: {alto}]
     [also: {contralti} (pl)]