epizoon > define
noun
- Any external parasitic organism (as fleas. ).
- synonyms: ectoparasite, ectozoan, ectozoon, epizoan
by WordNet 3.0 © 2006 by Princeton University
(n.) One of the artificial group of invertebrates of various kinds, which live parasitically upon the exterior of other animals; an ectozoon. Among them are the lice, ticks, many acari, the lerneans or fish lice, and other crustaceans.
by Webster's Revised Unabridged Dictionary