||Nem`a*toi"de*a (?), n. pl. [NL., fr. Gr. &?;, &?;, thread + -oid.] (Zoöl.) An order of worms, having a long, round, and generally smooth body; the roundworms. They are mostly parasites. Called also Nematodea, and Nematoda.

&fist; The trichina, stomach worm, and pinworm of man belong to this group. See also Vinegar eel, under Vinegar, and Gapeworm.