reservoir

American  

[rez-er-vwahr, -vwawr, -vawr, rez-uh-] / ˈrɛz ərˌvwɑr, -ˌvwɔr, -ˌvɔr, ˈrɛz ə- /

noun

1. a natural or artificial place where water is collected and stored for use, especially water for supplying a community, irrigating land, furnishing power, etc.

2. a receptacle or chamber for holding a liquid or fluid.

3. Geology. pool16

4. Biology. a cavity or part that holds some fluid or secretion.

5. a place where anything is collected or accumulated in great amount.

   Synonyms:

   stockpile, fund, pool, store, hoard

6. a large or extra supply or stock; reserve.

   a reservoir of knowledge.

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reservoir British  

/ ˈrɛzəˌvwɑː /

noun

1. a natural or artificial lake or large tank used for collecting and storing water, esp for community water supplies or irrigation

2. a receptacle for storing gas, esp one attached to a stove

3. biology a vacuole or cavity in an organism, containing a secretion or some other fluid

4. anatomy another name for cisterna

5. a place where a great stock of anything is accumulated

6. a large supply of something; reserve

   a reservoir of talent

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reservoir Scientific  

/ rĕz′ər-vwär′ /

1. A natural or artificial pond or lake used for the storage of water.

2. An underground mass of rock or sediment that is porous and permeable enough to allow oil or natural gas to accumulate in it.

3. An organism that is the host for a parasitic pathogen or that directly or indirectly transmits a pathogen to which it is immune.

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Etymology

Origin of reservoir

1680–90; < French réservoir, equivalent to réserv ( er ) to reserve + -oir -ory ²

Explanation

The word reservoir refers to a place where large amounts of water get stored. It can also be used to describe great amounts of other things, such as when you refer to a trivia expert as a reservoir of useless knowledge. The word reservoir comes from the French réservoir, which further derives from the Old French reserver, meaning "to reserve." Knowing this, it makes sense that the meaning evolved into a place, either man-made or natural, where water is stored or "reserved," usually for distribution for drinking, irrigating, and generating power. Remembering the related word reserve might also help in both the spelling and pronunciation of the word, as reserve is spelled (and pronounced) with "er," the same as "reservoir."

Example Sentences

Firefighters are currently responding to the fires near Claerwen Reservoir and Teifi Pools, and have urged people not to visit the area.

From BBC • Apr. 29, 2026

The Silver Lake Reservoir is a popular destination for joggers and walkers and has been considered a relatively safe public space for the Los Angeles community.

From Los Angeles Times • Apr. 22, 2026

The federal government, acting under a 2019 drought agreement, will release between 660,000 acre-feet and 1 million acre-feet from Flaming Gorge Reservoir over the next 12 months.

From Los Angeles Times • Apr. 17, 2026

New additions to the cast include Dune actress Rebecca Ferguson, Reservoir Dogs actor Tim Roth and Saltburn star Barry Keoghan, who plays Shelby's son.

From BBC • Mar. 2, 2026

Annabelle can see the blue of Bair Reservoir sparkling away with tiny diamonds of cheer.

From "A Heart in a Body in the World" by Deb Caletti

Related Words

• basin
• cistern
• container
• lake
• pond
• pool
• reserve
• source
• stockpile
• storage
• supply
• tank