otacoustic
Related to otacoustic: otoacoustic
ot`a`cous´tic
a. | 1. | Assisting the sense of hearing; as, an otacoustic instrument. |
n. | 1. | An instrument to facilitate hearing, as an ear trumpet. |
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.