%sonometer%

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. [ 1913 Webster ]

2. An instrument for testing the hearing capacity. [ 1913 Webster ]