Har*mon"i*phon (här*m&obreve;n"&ibreve;*f&obreve;n), n. [Gr. "armoni`a harmony + fwnh` sound.] (Mus.) An obsolete wind instrument with a keyboard, in which the sound, which resembled the oboe, was produced by the vibration of thin metallic plates, acted upon by blowing through a tube.