ossicle

noun5

1. •
   A small bone (or bony structure), especially one of the three of the middle ear.

   • The incus is one of the three auditory ossicles.
2. •
   Bone-like joint or plate.
3. •
   One of numerous small calcareous structures forming the skeleton of certain echinoderms, as the starfishes.

   • The skeleton of echinoderms is made of ossicles, linked to each other via muscles and connective tissue.
4. •
   One of the hard articuli or joints of the stem or branches of a crinoid or encrinite.
5. •
   One of the several small hard chitinous parts or processes of the gastric skeleton of crustaceans, as in the stomach of a lobster or crawfish.