The Collaborative International Dictionary
otacoustic
otacoustic \ot`a*cous"tic\, a. [Oto- + acoustic: cf. F. otacoustique.] Assisting the sense of hearing; as, an otacoustic instrument.
otacoustic
otacoustic \ot`a*cous"tic\, otacousticon \ot`a*cous"ti*con\, n. An instrument to facilitate hearing, as an ear trumpet.
Wiktionary
otacoustic
a. Assisting the sense of hearing. n. An ear trumpet.