pinworm > define
noun
- Small threadlike worm infesting human intestines and rectum especially in children.
- synonyms: threadworm, Enterobius vermicularis
by WordNet 3.0 © 2006 by Princeton University
(n.) A small nematoid worm (Oxyurus vermicularis), which is parasitic chiefly in the rectum of man. It is most common in children and aged persons.
by Webster's Revised Unabridged Dictionary