Phoneidoscope
Pronunciation : Pho*nei"do*scope
Part of Speech : n.
Etymology : [Phono- + Gr. -scope.] (Physics)
Definition : Defn: An instrument for studying the motions of sounding bodies by optical means. It consists of a tube across the end of which is stretched a film of soap solution thin enough to give colored bands, the form and position of which are affected by sonorous vibrations.
Source : Webster's Unabridged Dictionary, 1913