'Epizoon' definitions:

Definition of 'epizoon'

noun

Any external parasitic organism (as fleas) [syn: ectoparasite, ectozoan, ectozoon, epizoan, epizoon]

From: GCIDE

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 the lice, ticks, many acari, the lerneans, or fish lice, and other crustaceans. [1913 Webster]