Source : Webster's Revised Unabridged Dictionary (1913)

Stapes \Sta"pes\, n. [LL., a stirrup.] (Anat.)
   The innermost of the ossicles of the ear; the stirrup, or
   stirrup bone; -- so called from its form. See Illust. of
   {Ear}.

Source : WordNet®

stapes
     n : the stirrup-shaped ossicle that transmits sound from the
         incus to the cochlea [syn: {stirrup}]
     [also: {stapedes} (pl)]