res·er·voir | \ˈre-zə-ˌvwär, -zər-, -ˌvwȯr also -ˌvȯi \

Definition of reservoir 

1 : a place where something is kept in store: such as

a : an artificial lake where water is collected and kept in quantity for use

b : a part of an apparatus in which a liquid is held

c : supply, store a large reservoir of educated people

2 : an extra supply : reserve

3 : an organism in which a parasite that is pathogenic for some other species lives and multiplies usually without damaging its host

Keep scrolling for more

Examples of reservoir in a Sentence

The pen has a large ink reservoir. Colleges and universities provide reservoirs of talent for job recruiters. She found the reservoirs of energy she needed to finish the job.
See More

Recent Examples on the Web

The fire in a mountain area near a popular fishing reservoir grew to about 78 square miles (201 square kilometers) but containment also increased, authorities said Monday. Colleen Slevin, The Seattle Times, "Illegal fires ignite massive Colorado blazes, spur arrests," 10 July 2018 Utah authorities ordered more residents to evacuate as a blaze grew to about 62 square miles near a popular fishing reservoir amid high wind gusts, steep terrain, and dry conditions., "Wildfires keep growing in US West," 4 July 2018 Andrew Phelps said late Tuesday that a technical glitch had cut off crucial information: that the alert concerned elevated levels of a natural toxin in a local reservoir. NBC News, "Oregon official apologizes after cryptic emergency alert alarms residents," 30 May 2018 In the foothills east of Napa The lake: Hennessey, a reservoir formed by the Conn Creek Dam, is a great spot for kayaks and other self-powered vehicles or boats with electric motors. Tom Stienstra,, "Sunday getaway to Lake Hennessey," 24 June 2018 Santa Fe Lake, just a half-mile south of downtown, is a reservoir trapped behind a red sandstone dam that was built by the railroad. Roger Naylor, azcentral, "Arizona road trip: Williams has Route 66, Bearizona and cool summer fun," 15 June 2018 The closest ski resort to the fire, Keystone, is about 8 miles (12.8 kilometers) away and across a large reservoir. Colleen Slevin,, "New wildfire erupts near Colorado ski resorts, houses," 12 June 2018 This seasonal cycle repeated through time and could come from an underground reservoir of methane, the study says. Alessandra Potenza, The Verge, "NASA’s Curiosity rover discovers that methane on Mars changes with the seasons," 7 June 2018 Instagram user Alex Kalange recently posted two videos of himself taking a plunge into a snow-making reservoir from the Gold Coast Express chairlift. Noel Harris, sacbee, "Here's what jumping off a chairlift into a reservoir at Squaw Valley will get you," 31 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'reservoir.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of reservoir

1690, in the meaning defined at sense 1

History and Etymology for reservoir

French réservoir, from Middle French, from reserver

Keep scrolling for more

Learn More about reservoir

Statistics for reservoir

Last Updated

19 Oct 2018

Look-up Popularity

Time Traveler for reservoir

The first known use of reservoir was in 1690

See more words from the same year

Keep scrolling for more

More Definitions for reservoir



English Language Learners Definition of reservoir

: a usually artificial lake that is used to store a large supply of water for use in people's homes, in businesses, etc.

: a place (such as a part of a machine) where a liquid is stored

: an extra supply of something


res·er·voir | \ˈre-zər-ˌvwär \

Kids Definition of reservoir

: a place where something (as water) is kept in store for future use


res·er·voir | \ˈrez-ə(r)v-ˌwär, -ə(r)v-ˌ(w)ȯr \

Medical Definition of reservoir 

1 : a space (as an enlargement of a vessel or the cavity of a glandular acinus) in which a body fluid is stored

2 : an organism in which a parasite that is pathogenic for some other species lives and multiplies without damaging its host also : a noneconomic organism within which a pathogen of economic or medical importance flourishes without regard to its pathogenicity for the reservoir rats are reservoirs of plague — compare carrier sense 1a

Keep scrolling for more

Comments on reservoir

What made you want to look up reservoir? Please tell us where you read or heard it (including the quote, if possible).


a state of commotion or excitement

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Roman Mythology Quiz

  • the-triumph-of-venus-by-alessandro-magnasco
  • Boreal comes from the name of the ancient Greek god of which wind?
True or False

Test your knowledge - and maybe learn something along the way.

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!