reservoir Definition

reservoir
noun

1. A large natural or man-made lake, or a tank, in which water is collected and stored for public use, irrigation, etc.
2. A part of a machine, device, etc where liquid is stored.
3. biol.
Part of an animal or plant in which fluid is retained.
4. A large reserve or supply of something, eg of creativity, talent, etc.

Thesaurus: store, supply, stock, stockpile, repository, reserves, source.
5. A place where a large supply of something, now especially of fluid or vapour, is collected and stored.

Etymology: 17c: from French réservoir, from réserver to reserve.