Source : Webster's Revised Unabridged Dictionary (1913)

Sonometer \So*nom"e*ter\, n. [L. sonus a sound + -meter.]
   1. (Physiol.) An instrument for exhibiting the transverse
      vibrations of cords, and ascertaining the relations
      between musical notes. It consists of a cord stretched by
      weight along a box, and divided into different lengths at
      pleasure by a bridge, the place of which is determined by
      a scale on the face of the box.

   2. An instrument for testing the hearing capacity.

Source : WordNet®

sonometer
     n : an instrument used to measure the sensitivity of hearing
         [syn: {audiometer}]