What does villus mean?
A villus is a small projection on the surface of an organ, tissue, or plant. Its best-known meaning is anatomical: the lining of the small intestine is covered with millions of finger-like projections called villi. These structures increase the surface area available for absorbing digested nutrients, and each contains a network of blood capillaries and a lymphatic vessel known as a lacteal. The term can also describe a fine, soft, hair-like outgrowth in plants. In medical writing, villus is normally used in the singular when discussing one projection, as in “an intestinal villus,” while villi refers to the structures collectively. The word is technical rather than everyday, and it is especially associated with discussions of intestinal structure, absorption, and disorders involving damage to the intestinal lining.
nounA small, slender, finger-like projection on the surface of a body or organ, especially one of the numerous projections lining the small intestine. In botany, the term can also refer to a long, soft hair or hair-like outgrowth.
- A slender, finger-like projection from the surface of an organ or tissue, especially in the small intestine.
- A long, soft, hair-like outgrowth, especially in plants.
"Each intestinal villus contains blood vessels and a lymphatic vessel called a lacteal."
"A single intestinal villus is too small to see without a microscope."
"The biopsy showed damage to an intestinal villus, a finding consistent with villous atrophy."
The standard plural is villi, as in intestinal villi.
"The small intestine contains millions of villi that help absorb nutrients."
Although one villus is microscopic, millions of these tiny projections give the small intestine an enormous absorptive surface.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does villus come from?
The English word comes from Latin villus, meaning “hair,” “tuft,” or “shaggy hair.” The Latin term was borrowed into English in a technical anatomical sense and later came to denote fine projections on biological surfaces. Related forms include the English adjective villous and the Latin-derived adjective villose; the plural villi reflects the regular Latin plural of villus.
Related word forms
How villus is actually used
The word is chiefly used in medicine and biology. In anatomical contexts, the singular is villus and the plural is villi; in botanical contexts, it may refer to a fine, soft hair or hair-like projection.
Easily confused with villus
Villus is the singular form, while villi is the usual plural, especially in the term intestinal villi.