Villus

Part of speech: noun

Pronunciation: /ˈvɪləs/

Definitions

1. A tiny, finger-like projection that resides on the surface of the intestines and facilitates the absorption of nutrients in the digestive system
2. A small, hair-like outgrowth from various membranes that plays a crucial role in increasing the absorption area within the gastrointestinal tract
3. A microscopic, finger-shaped structure found on the lining of the intestines that enhances nutrient uptake during digestion

Etymology: The Latin "villus" meant "shaggy hair," the coarse, tufted kind found on an animal's coat, and that physical picture is still visible in the anatomical term. English borrowed it directly from Latin for the microscopic projections lining the small intestine, which are packed so densely that they multiply the surface available for absorbing nutrients. A single word for shaggy hair thus ended up naming structures far too small to see without a microscope. The word has a plural, "villi," which is the form most often used in anatomy textbooks. Because "villus" is a Latin noun, the plural follows the Latin second-declension pattern, and English writers continue to use it rather than adding an English "s."