\Mal"le*us\, n.; pl. {Mallei}. [L., hammer. See {Mall} a
beetle.]
1. (Anat.) The outermost of the three small auditory bones,
   ossicles; the hammer. It is attached to the tympanic
   membrane by a long process, the handle or manubrium. See
   Illust. of {Far}.
2. (Zo["o]l.) One of the hard lateral pieces of the mastax of
   Rotifera. See {Mastax}.
3. (Zo["o]l.) A genus of bivalve shells; the hammer shell.