NOUN (2)

1. the fatty flesh of eel; an elongate fish found in fresh water in Europe and America; large eels are usually smoked or pickled;

2. voracious snakelike marine or freshwater fishes with smooth slimy usually scaleless skin and having a continuous vertical fin but no ventral fins;

The Collaborative International Dictionary of English v.0.48:

Eel \Eel\, n. [AS. ?l; akin to D., G., & Dan. aal, Icel. [=a]ll,
   Sw. [*a]l.] (Zo["o]l.)
   An elongated fish of many genera and species. The common eels
   of Europe and America belong to the genus Anguilla. The
   electrical eel is a species of Gymnotus. The so called
   vinegar eel is a minute nematode worm. See Conger eel,
   Electric eel, and Gymnotus.
   [1913 Webster]

WordNet (r) 3.0 (2006):

eel
    n 1: the fatty flesh of eel; an elongate fish found in fresh
         water in Europe and America; large eels are usually smoked
         or pickled
    2: voracious snakelike marine or freshwater fishes with smooth
       slimy usually scaleless skin and having a continuous vertical
       fin but no ventral fins