• (n.) An instrument for measuring the acuteness of the sense of hearing.
A·cou'me·ter noun [ Greek ... to hear + -meter .] (Physics.) An instrument for measuring the acuteness of the sense of hearing. Itard. 
acoumeter An instrument used for estimating the power or extent of the sense of hearing before the introduction of audiometers. Variant spellings include these words: acouometer, acoumeter, acousmeter, acousmetric, acousmometric, acoumetry, and acoumetric.