Villus \Vil"lus\, n.; pl. Villi. [L., shaggy hair, a tuft of hair.]

1. (Anat.) One of the minute papillary processes on certain vascular membranes; a villosity; as, villi cover the lining of the small intestines of many animals and serve to increase the absorbing surface.

2. pl. (Bot.) Fine hairs on plants, resembling the pile of velvet.

Source: Webster's Revised Unabridged Dictionary (1913)