Source : Webster's Revised Unabridged Dictionary (1913)

Soprano \So*pra"no\, n.; pl. E. {Sopranos}, It. {Soprani}. [It.,
   fr. soprano superior, highest, fr. sopra above, L. supra. See
   {Sovereign}.] (Mus.)
   (a) The treble; the highest vocal register; the highest kind
       of female or boy's voice; the upper part in harmony for
       mixed voices.
   (b) A singer, commonly a woman, with a treble voice.

Source : WordNet®

soprano
     adj : having or denoting a high range; "soprano voice"; "soprano
           sax"; "the boy still had a fine treble voice"; "the
           treble clef" [syn: {treble}]
     [also: {soprani} (pl)]

soprano
     n 1: a female singer
     2: the highest female voice; the voice of a boy before puberty
     3: the pitch range of the highest female voice [syn: {treble}]
     [also: {soprani} (pl)]