phoneidoscope Meaning, Definition & Usage

Pho*nei"do*scope noun
Phono- + Gr. form + -scope.
  1. (Physics) 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.

Webster 1913