Source : Webster's Revised Unabridged Dictionary (1913)

Tetrapod \Tet"ra*pod\, n. [Gr. ? fourfooted; te`tra- (see
   {Tetra-}) + ?, ?, foot.] (Zo["o]l.)
   An insect characterized by having but four perfect legs, as
   certain of the butterflies.

Source : WordNet®

tetrapod
     n : a vertebrate animal having four feet or legs or leglike
         appendages