villus

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Biology A minute projection arising from a mucous membrane, especially:
2. n. Biology One of the numerous vascular projections of the small intestine.
3. n. Biology One of the fingerlike projections of the chorion that contribute to the formation of the placenta in mammals.
4. n. Botany A fine, hairlike epidermal outgrowth.

Century Dictionary and Cyclopedia

1. n. In anatomy: One of numerous minute vascular projections from the mucous membrane of the intestine, of a conical, cylindric, clubbed, or filiform shape, consisting essentially of a lacteal vessel as a central axis, with an arteriole and a veinlet, inclosed in a layer of epithelium, with the basement membrane and muscular tissue of the mucous membrane, and cellular or reticular tissue. The villi occur chieflly in the small intestine, and especially iu the upper part of that tube; there are estimated to be several millions in man; they collectively constitute the beginnings of the absorbent or lacteal vessels of the intestine. See also cut under lymphatic.
2. n. One of the little vascular tufts or processes of the shaggy chorion of an ovum or embryo, in later stages of development entering into the formation of the fetal part of the placenta. See cut under uterus, Some villiform part or process of various animals. See cut under hydranth.
3. n. In botany, one of the long, straight, and soft, hairs which sometimes cover the fruit, flowers, and other parts of plants.

Wiktionary

1. n. biology a small projection from a mucous membrane, particularly those found in the intestines

GNU Webster's 1913

1. n. (Anat.) One of the minute papillary processes on certain vascular membranes; a villosity.
2. n. (Bot.) Fine hairs on plants, resembling the pile of velvet.

WordNet 3.0

1. n. a minute hairlike projection on mucous membrane