\Max*il"la\, n.; pl. {Maxill[ae]}. [L., dim. of mala
jaw, jawbone.]
1. (Anat.)
   (a) The bone of either the upper or the under jaw.
   (b) The bone, or principal bone, of the upper jaw, the
       bone of the lower jaw being the mandible. [Now
       commonly used in this restricted sense.]
2. (Zo["o]l.) One of the lower or outer jaws of arthropods.
Note: There are usually two pairs in Crustacea and one pair
      in insects. In certain insects they are not used as
      jaws, but may form suctorial organs. See Illust. under
      {Lepidoptera}, and {Diptera}.