Ep`i*zo"on (?), n.; pl. Epizoa (#). [NL., fr. Gr. upon + animal.] Zool.
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.
© Webster 1913.