reservoir

IPA/ˈrezəvwɑː(r)/
KK[rˈɛzəvwˌɑr]IPA/ˈrezərvwɑːr/

reservoir — noun

  • reservoirsingular
  • reservoirsplural

1. a body of water, either formed by nature or created by people, that is kept to s

1.nounB2
Definition

a body of water, either formed by nature or created by people, that is kept to supply fresh water to towns, farms, and other places.

Example

The town gets its drinking water from a large reservoir in the hills.

During the drought, the reservoir behind the dam dropped to half its normal level.

preposition pattern: behind the dam

Common collocations
  • build a reservoir
  • reservoir level
  • drinking water reservoir
  • fill the reservoir
  • behind the dam
Synonyms
  • lake

    a natural body of water, not necessarily used as a water supply

  • basin

    a natural or man-made hollow that holds water, typically smaller than a reservoir

  • tank

    a fully enclosed container for liquid, usually smaller and man-made

Grammar Patterns

reservoir + of + noun

reservoir + behind/in/at + noun phrase

Usage Note

Frequently followed by a prepositional phrase that names the location (behind the dam, in the hills) or the substance stored (of water, of drinking water).

Common Mistakes

We keep emergency drinking water in a small reservoir on the roof.
We keep emergency drinking water in a small tank on the roof.
A reservoir is usually a large outdoor body of water, not a household container.

2. a plentiful store of something abstract, such as knowledge, patience, or goodwil

2.nounB2
Definition

a plentiful store of something abstract, such as knowledge, patience, or goodwill, that is available when needed.

Example

The elderly woman had a deep reservoir of patience gained from years of teaching.

typical pattern: a deep reservoir of [abstract noun]

Padma discovered a reservoir of talent in her students that no one had noticed before.

Common collocations
  • reservoir of talent
  • deep reservoir of patience
  • rich reservoir of experience
  • vast reservoir of knowledge
Synonyms
  • store

    more general, less literary; can be concrete or abstract

  • supply

    emphasises that the resource is available for use

  • pool

    suggests a shared resource contributed by multiple people

  • fund

    often implies a financial or countable supply

Grammar Patterns

a/their + reservoir + of + abstract noun

Usage Note

The stored resource is nearly always specified by a following of-phrase (e.g. a reservoir of goodwill). Unlike sense 1, this sense is metaphorical — the store is intangible (knowledge, energy, trust) rather than physical water.

Word family

Synonym discussion

Sense: noun/1

A lake is a natural body of water surrounded by land, formed by geological processes without direct human construction. A reservoir is a body of water — either a natural lake modified by people or an artificial basin built by damming a river — that is deliberately kept and managed to supply water to homes, farms, and industries. A dam is the wall or barrier itself, built across a river to hold back the water and create a reservoir. In short: a lake can exist without any human engineering; a reservoir is a lake (or artificial basin) managed as a water source; a dam is the structure that creates the reservoir. For example, the Hsinchu area relies on a reservoir (not a natural lake) for its water supply, and the concrete wall that holds the water back is the dam.

lake ↗reservoir ↗dam ↗

Common collocations

Phrases

  • a reservoir of

Prepositions

Etymology

LatinFrenchEnglish

Reservoir came into English from French réservoir, which was formed from the verb réserver (to set aside or keep back). The French verb traces back to Latin reservare, meaning 'to keep back' or 'save up'. The word originally referred to a place where things are stored for future use, and that core idea remains in both the physical water-storage sense and the later abstract sense.