reservoir

American  

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

noun

reservoirs plural

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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Other Word Forms

Noun Inflected Forms

• reservoirs
  plural

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

See Examples For:

reservoir reservoirs

That reservoir of credit card-powered miles helps feed demand, allowing airlines to report strong revenue despite volatile jet-fuel prices and broader economic jitters.

From The Wall Street Journal ● Jul. 17, 2026

Liulan was not the only reservoir that burst, locals told AFP Thursday -- another smaller one near the town of Gantang also collapsed.

From Barron's ● Jul. 9, 2026

This enormous reservoir of hot gas contains far more mass than all of the galaxies in the cluster combined.

From Science Daily ● Jul. 4, 2026

Southern Water said investment in infrastructure, including the UK's first new reservoir for 30 years, would help stop it taking water from the Test and Itchen rivers by 2040.

From BBC ● Jul. 3, 2026

I dipped a few ladles of warm water from the stove’s reservoir into the largest enamel bowl, then dropped in a bar of soap and rolled it into a lather.

From "Hattie Big Sky" by Kirby Larson

The break, which happened early Thursday, was on a riveted steel pipe from 1916 that forms the major arteries for water delivery from reservoirs and tanks to smaller distribution mainlines across Los Angeles.

From Los Angeles Times ● Jul. 17, 2026

England's reservoirs are at roughly average levels for the time of year, albeit with some variation across the country.

From BBC ● Jul. 15, 2026

"Due to the impact of persistent heavy rainfall and the prolonged passage of floodwaters at high levels, the safety of reservoirs and embankments in the affected areas faces a severe test," he said.

From Barron's ● Jul. 7, 2026

Twenty-five years after the initial release of “A.I. Artificial Intelligence,” technology has nearly depleted humanity’s emotional reservoirs.

From Salon ● Jun. 28, 2026

It was the fortuitous conjunction of these two vast reservoirs of philosophical and physical wealth that defined America's national interest and made it so special.

From "Founding Brothers: The Revolutionary Generation" by Joseph J. Ellis

Related Words

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