Source : Webster's Revised Unabridged Dictionary (1913)

Metallophone \Me*tal"lo*phone\, n. [L. metallum metal + Gr. ?
   sound.] (Music)
   (a) An instrument like a pianoforte, but having metal bars
       instead of strings.
   (b) An instrument like the xylophone, but having metallic
       instead of wooden bars.