Merriam-Webster Collegiate Dictionary - villus

 noun  (plural villi)  Etymology: New Latin, from Latin, tuft of shaggy hair — more at velvet  Date: 1728 a small slender often vascular process: as  a. one of the minute finger-shaped processes of the mucous membrane of the small intestine that serve in the absorption of nutriment  b. one of the branching processes of the surface of the chorion of the developing embryo of most mammals that help to form the placenta