Source : Webster's Revised Unabridged Dictionary (1913)

Otoscope \O"to*scope\, n. [Oto- + -scope.]
   An instrument for examining the condition of the ear.

Source : WordNet®

otoscope
     n : medical instrument consisting of a magnifying lens and
         light; used for examining the external ear (the auditory
         meatus and especially the tympanic membrane)