reservoir

noun

res·​er·​voir ˈre-zə-ˌvwär How to pronounce reservoir (audio) -zər- How to pronounce reservoir (audio) -ˌvwȯr How to pronounce reservoir (audio)
 also  -ˌvȯi
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
a
: a host organism in which an infectious agent (such as a bacterium or virus) that is pathogenic for some other species lives and multiplies typically without damaging the host

Note: A reservoir serves as a source from which transmission of infection and outbreaks of disease can occur.

It is the white-footed mouse that serves as a natural reservoir host for the spirochete B. [Borrelia] burgdorferi. These mice carry the spirochete without any apparent harm to themselves, and it is through feeding on infected mice that the immature stages of the tick acquire the spirochete.Suzanne Clothier et al.
also : a nonliving thing (such as soil or water) in which an infectious agent lives and multiplies and which serves as a source of infection similar to a host organism
b
: a part of the body that harbors an infectious agent and serves as a source of reinfection or infection transmission
… vulvar or rectal reservoirs, which might increase risk for BV [bacterial vaginosis] recurrence.Lisa E. Manhart et al.
compare carrier sense 5a, vector entry 1 sense 2a

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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Use hot water and a small scrub brush to get inside the reservoir and ports, and avoid using soaps, which can leave harmful residues, says Witko. Arricca Elin Sansone, Southern Living, 14 Apr. 2025 Lake Oroville, the capstone of the state reservoir system, was at 120% of its historical average on Friday, state data shows. Sharon Bernstein, Sacbee.com, 11 Apr. 2025 The Sierra Nevada snowpack provides about 30 percent of California's water, gradually melting to replenish rivers, reservoirs and groundwater. Hannah Parry, MSNBC Newsweek, 3 Apr. 2025 The top part also has a small reservoir that keeps 60 milliliters of water in the tray at all times, ensuring your kitty always has access to water. Simon Hill, Wired News, 31 Mar. 2025 See All Example Sentences for reservoir

Word History

Etymology

French réservoir, from Middle French, from reserver

First Known Use

1690, in the meaning defined at sense 1

Time Traveler
The first known use of reservoir was in 1690

Browse Nearby Words

Cite this Entry

“Reservoir.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reservoir. Accessed 22 Apr. 2025.

Kids Definition

reservoir

noun
1
: a place where something is kept in store
especially : an artificial or natural lake where water is collected as a water supply
2
: an extra supply : reserve
3
: a living thing (as a fly or mouse) in which a parasite (as a bacterium) that is harmful to some other living thing lives and multiplies
Etymology

from French réservoir "place where something is kept in reserve," from reserver "to reserve, keep for future use"

Medical Definition

reservoir

noun
1
: a space (as an enlargement of a vessel or the cavity of a glandular acinus) in which a body fluid is stored
2
a
: a host organism in which an infectious agent (as a bacterium or virus) that is pathogenic for some other species lives and multiplies typically without damaging the host

Note: A reservoir serves as a source from which transmission of infection and outbreaks of disease can occur.

Wild rodents also constitute a reservoir of hantaviruses. The viruses are shed in urine, droppings, and saliva, and humans are mainly infected aerogenically by inhaling aerosols containing the virus.Hilde Kruse et al., Emerging Infectious Diseases
also : a nonliving thing (as soil or water) in which an infectious agent lives and multiplies and which serves as a source of infection similar to a host organism
b
: a part of the body that harbors an infectious agent and serves as a source of reinfection or infection transmission
… vulvar or rectal reservoirs, which might increase risk for BV [bacterial vaginosis] recurrence.Lisa E. Manhart et al., Infectious Diseases in Obstetrics and Gynecology
carrier sense 1a, vector entry 1 sense 2

More from Merriam-Webster on reservoir

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