Definition of: reservoir

(rez′ər·vwôr, -vwär, -vôr) noun
1. A receptacle where some material, especially of a liquid or gas, may be kept in store.
2. A basin, either natural or artificial, for collecting and containing a supply of water, as for use in a city or for water power.
3. An attachment to a stove, machine, or instrument, for containing a fluid to be used in its operation: the reservoir of a lamp.
4. An extra supply; a store of anything. [<F réservoir]