Any external parasitic organism (as fleas)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Epizoon \Ep`i*zo"["o]n\, n.; pl. Epizoa . [NL., fr. Gr. 'epi` upon + zw^,on animal.] (Zo["o]l.) One of the artificial group of invertebrates of various kinds, which live parasitically upon the exterior of other animals; an ectozo["o]n. Among them are ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"parasitic animal on the surface or in the skin of another," 1836, from epi- "on" + Greek zoon "animal" (see zoo- ).

WordNet Word definitions in WordNet
n. any external parasitic organism (as fleas) [syn: ectoparasite , ectozoan , ectozoon , epizoan ]

Wiktionary Word definitions in Wiktionary
n. (context biology English) An external animal parasite