\Tet"ro*don\, n. [Tetra- + Gr. ?, ?, tooth.] (Zo["o]l.)
Any one of numerous species of plectognath fishes belonging
to {Tetrodon} and allied genera. Each jaw is furnished with
two large, thick, beaklike, bony teeth. [Written also
{tetradon}.]
Note: The skin is usually spinous, and the belly is capable
      of being greatly distended by air or water. It includes
      the swellfish, puffer
(a), and similar species.