‖n. pl. [ NL. ] (Zool.) (a) An artificial group formerly made for parasitic insects, as lice, ticks, mites, etc. (b) A division of copepod Crustacea, having a sucking mouth, as the lerneans. They are mostly parasites on fishes. Called also Siphonostomata. [ 1913 Webster ]

a. (Bot. & Zool.) Of or pertaining to parasites; parasitic. [ 1913 Webster ]