osteophone

from The Collaborative International Dictionary of English v.0.48
Osteophone \Os"te*o*phone\, n. [Gr. 'oste`on bone + fwnh`
   voice.]
   An instrument for transmission of auditory vibrations through
   the bones of the head, so as to be appreciated as sounds by
   persons deaf from causes other than those affecting the
   nervous apparatus of hearing.
   [1913 Webster]
    

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