[rez-er-vwahr, -vwawr, -vawr, rez-uh-]
a natural or artificial place where water is collected and stored for use, especially water for supplying a community, irrigating land, furnishing power, etc.
a receptacle or chamber for holding a liquid or fluid.
Geology, See under pool1 ( def 6 ).
Biology. a cavity or part that holds some fluid or secretion.
a place where anything is collected or accumulated in great amount.
a large or extra supply or stock; reserve: a reservoir of knowledge.

1680–90; < French réservoir, equivalent to réserv(er) to reserve + -oir -ory2

5. store, pool, fund, stockpile, hoard. Unabridged


1 [pool]
a small body of standing water; pond.
a still, deep place in a stream.
any small collection of liquid on a surface: a pool of blood.
a puddle.
a subterranean accumulation of oil or gas held in porous and permeable sedimentary rock (reservoir)
verb (used without object)
to form a pool.
(of blood) to accumulate in a body part or organ.
verb (used with object)
to cause pools to form in.
to cause (blood) to form pools.
of or for a pool: pool filters.
taking place or occurring around or near a pool: a pool party.

before 900; Middle English; Old English pōl; cognate with Dutch poel, German Pfuhl Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
pool1 (puːl)
1.  a small body of still water, usually fresh; small pond
2.  a small isolated collection of liquid spilt or poured on a surface; puddle: a pool of blood
3.  a deep part of a stream or river where the water runs very slowly
4.  an underground accumulation of oil or gas, usually forming a reservoir in porous sedimentary rock
5.  See swimming pool
[Old English pōl; related to Old Frisian pōl, German Pfuhl]

pool2 (puːl)
1.  any communal combination of resources, funds, etc: a typing pool
2.  the combined stakes of the betters in many gambling sports or games; kitty
3.  commerce a group of producers who conspire to establish and maintain output levels and high prices, each member of the group being allocated a maximum quota; price ring
4.  chiefly (US) finance
 a.  a joint fund organized by security-holders for speculative or manipulative purposes on financial markets
 b.  the persons or parties involved in such a combination
5.  any of various billiard games in which the object is to pot all the balls with the cue ball, esp that played with 15 coloured and numbered balls; pocket billiards
6.  to combine (investments, money, interests, etc) into a common fund, as for a joint enterprise
7.  commerce to organize a pool of (enterprises)
8.  informal (Austral) to inform on or incriminate (someone)
[C17: from French poule, literally: hen used to signify stakes in a card game, from Medieval Latin pulla hen, from Latin pullus young animal]

reservoir (ˈrɛzəˌvwɑː)
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
[C17: from French réservoir, from réserver to reserve]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

1690, "a place where something tends to collect," from Fr. réservoir "storehouse," from O.Fr. reserver "to reserve" (see reserve). Specific meaning "artificial basin to collect and store a large body of water" is from 1705.

"small body of water," O.E. pol, from W.Gmc. *pol- (cf. O.Fris., M.L.G. pol, Du. poel, O.H.G. pfuol, Ger. Pfuhl). As a short form of swimming pool it is recorded from 1921.

"game similar to billiards," 1848, originally (1693) a card game played for collective stakes (a "pool"), from Fr. poule "stakes, booty, plunder," lit. "hen," from O.Fr. poule "hen, young fowl." Perhaps the original notion is from jeu de la poule, supposedly a game in which people threw things at a hen
and the player who hit it, won it, which speaks volumes about life in the Middle Ages. The connection of "hen" and "stakes" is also present in Sp. polla and Walloon paie. Meaning "collective stakes" first recorded 1869; sense of "common reservoir of resources" is from 1917. Meaning "group of persons who share duties or skills" is from 1928. The verb meaning "to make a common interest, put things into a pool" is 1872, from the noun.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

pool (pōōl)
A collection of blood in any region of the body due to dilation and retardation of the circulation in capillaries and veins.

reservoir res·er·voir (rěz'ər-vwär', -vwôr', -vôr')

  1. A fluid-containing sac or cavity.

  2. An organism or a population that directly or indirectly transmits a pathogen while being virtually immune to its effects.

  3. A large or extra supply; a reserve.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
reservoir   (rěz'ər-vwär')  Pronunciation Key 
  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.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Bible Dictionary

Pool definition

a pond, or reservoir, for holding water (Heb. berekhah; modern Arabic, birket), an artificial cistern or tank. Mention is made of the pool of Gibeon (2 Sam. 2:13); the pool of Hebron (4:12); the upper pool at Jerusalem (2 Kings 18:17; 20:20); the pool of Samaria (1 Kings 22:38); the king's pool (Neh. 2:14); the pool of Siloah (Neh. 3:15; Eccles. 2:6); the fishpools of Heshbon (Cant. 7:4); the "lower pool," and the "old pool" (Isa. 22:9,11). The "pool of Bethesda" (John 5:2,4, 7) and the "pool of Siloam" (John 9:7, 11) are also mentioned. Isaiah (35:7) says, "The parched ground shall become a pool." This is rendered in the Revised Version "glowing sand," etc. (marg., "the mirage," etc.). The Arabs call the mirage "serab," plainly the same as the Hebrew word _sarab_, here rendered "parched ground." "The mirage shall become a pool", i.e., the mock-lake of the burning desert shall become a real lake, "the pledge of refreshment and joy." The "pools" spoken of in Isa. 14:23 are the marshes caused by the ruin of the canals of the Euphrates in the neighbourhood of Babylon. The cisterns or pools of the Holy City are for the most part excavations beneath the surface. Such are the vast cisterns in the temple hill that have recently been discovered by the engineers of the Palestine Exploration Fund. These underground caverns are about thirty-five in number, and are capable of storing about ten million gallons of water. They are connected with one another by passages and tunnels.

Easton's 1897 Bible Dictionary
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Encyclopedia Britannica


an open-air storage area (usually formed by masonry or earthwork) where water is collected and kept in quantity so that it may be drawn off for use.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
The political minefield alone is enough to deplete your emotional reservoir.
Both sides agree that if the dam is built, water levels at the new reservoir
  would fluctuate seasonally.
There was the stampede to see the migrating loon that chose the park's
  reservoir for a rest stop.
After you've filled the stand's reservoir with water, you're done.
Images for reservoir
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