English

Noun

otacousticon ‎(plural otacousticons)

1. (now rare) An instrument to aid hearing, such as an ear trumpet or hearing aid.
   • 1621, Robert Burton, The Anatomy of Melancholy, New York Review of Books, 2001, p.69:

     […] Gyges' invisible ring, or some rare perspective glass, or otacousticon, which would so multiply species that a man might hear and see all at once […].