Source : Webster's Revised Unabridged Dictionary (1913)

Gymnotus \Gym*no"tus\, n. [NL., fr. Gr. gymno`s naked + ? the
   back: cf. F. gymnote.] (Zo["o]l.)
   A genus of South American fresh-water fishes, including the
   {Gymnotus electricus}, or electric eel. It has a greenish,
   eel-like body, and is possessed of electric power.

         One fearful shock, fearful but momentary, like from the
         electric blow of the gymnotus.           --De Quincey.