The Collaborative International Dictionary of English v.0.48:

Copepod \Cop"e*pod\, a. (Zool.)
   Of or pertaining to the Copepoda. -- n. One of the Copepoda.
   [1913 Webster]

WordNet (r) 3.0 (2006):

copepod
    n 1: minute marine or freshwater crustaceans usually having six
         pairs of limbs on the thorax; some abundant in plankton and
         others parasitic on fish [syn: copepod, copepod
         crustacean]