1. [n]  a remedy for hearing loss or deafness
2. [adj]  of or relating to the science of acoustics; "acoustic properties of a hall"

Acoustic
Acoustic

more details ...

1. \A*cous"tic\ (#; 277), a. [F. acoustique, Gr. ?
   relating to hearing, fr. ? to hear.]
   Pertaining to the sense of hearing, the organs of hearing, or
   the science of sounds; auditory.
   {Acoustic duct}, the auditory duct, or external passage of
      the ear.
   {Acoustic telegraph}, a telegraph making audible signals; a
      telephone.
   {Acoustic vessels}, brazen tubes or vessels, shaped like a
      bell, used in ancient theaters to propel the voices of the
      actors, so as to render them audible to a great distance.
   

2. \A*cous"tic\, n.
   A medicine or agent to assist hearing.