Source : Webster's Revised Unabridged Dictionary (1913)

Plectognath \Plec"tog*nath\, a. (Zo["o]l.)
   Of or pertaining to the Plectognathi. -- n. One of the
   Plectognathi.

Source : WordNet®

plectognath
     n : tropical marine fishes having the teeth fused into a beak
         and thick skin covered with bony plates or spines [syn: {plectognath
         fish}]