Valves

Part of speech: noun

Definitions

1. Apparatuses that manage the movement of fluids within systems by either blocking or allowing passage
2. Mechanisms that enable or restrict the flow of liquids and gases according to pressure and demand
3. Mechanical components designed to open, close, or partially obstruct fluid channels ; anatomical features in the heart that maintain direction in blood circulation by preventing backflow

Etymology: "Valves" is the plural of "valve", a noun whose original sense was a physical door rather than a mechanical part. The Latin "valva" meant a double door, and the word's older sense of a leaf of a folding door survives in the way a valve pivots or folds to let something pass in one direction only. Middle English took the word from Latin, and it kept the image of a hinged panel swinging open or shut. The mechanical sense developed from that same idea: a panel that opens to admit flow and closes to stop it. Engineers and anatomists both borrowed the term for the moving parts that control passage in pipes, engines and the heart. The plural form simply names more than one such device.

Synonyms: gates, controls, closes

Antonyms: openings, holes