ectozoa

pl. [Gr. ektos without, outside, and zoon, pl. zōa =an animal.] Zool .: Animals parasitic on the outside of living bodies, as distinguished from Entozoa, animals parasitic within them. ěc-tro-pi-uŭm, s . [Gr. ektropion , from ektropos =a turning out of the way: ek out, and tropos =a turn; trepo =to turn.] Med.: An everted eyelid, produced either by a tumefaction of the inner membrane or by a contraction of the skin covering the eyelids.