res·er·voir (rĕzər-vwär′, -vwôr′, -vôr′)
1. A natural or artificial pond or lake used for the storage and regulation of water.
2. A receptacle or chamber for storing a fluid.
3. An underground accumulation of petroleum or natural gas.
4. Anatomy See cisterna.
5. A large or extra supply; a reserve: a reservoir of goodwill.
6. Medicine An organism or population that directly or indirectly transmits a pathogen while being virtually immune to its effects.
[French réservoir, from réserver, to reserve, from Old French reserver; see RESERVE.]
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