heavy water

noun

Updated on: 18 Mar 2018

Definition of heavy water

1 : the compound D₂O composed of deuterium and oxygen — called also deuterium oxide

2 : water enriched in deuterium

Recent Examples of heavy water from the Web

The Sacramento region, where lawns are big and summers are hot, traditionally has been one of the heaviest water users in the state.

— dale kasler and ryan sabalow, sacbee, "Why your water provider is fighting California's ban on watering sidewalks | The Sacramento Bee," 15 Mar. 2018
Combined with running faucets, heavy water consumption amid the freeze caused pressure to plummet in the utility's system and prompted a precautionary boil-water advisory for the entire east bank Thursday morning.

— beau evans, NOLA.com, "Seniors struggle in Lower 9th Ward amid boil advisory," 19 Jan. 2018
Hitler’s heavy water experiments and his V2 rockets would have ultimately made opposition impossible.

— john kass, chicagotribune.com, "In 'Darkest Hour,' Churchill refuses to bend the knee," 15 Dec. 2017
Shoshone Falls, which boasted some of the heaviest water flows in years this spring, came roaring back to life on the Snake River this week.

— christina lords, idahostatesman, "Miss the extraordinary flows at Shoshone Falls this spring? Here’s a second chance.," 14 Dec. 2017
Haley pointed to breaches in the amount of heavy water that Iran was allowed to have and refusal to open up all its sites for inspection as grounds for labeling Iran as noncompliant.

— loveday morris, Washington Post, "Fix or nix the Iran nuclear deal, Netanyahu demands ahead of Trump meeting," 13 Sep. 2017
Iran’s supply of heavy water, used in reactors that can produce plutonium, another nuclear-weapons fuel, also was within the limits, the report stated.

— david e. sanger and rick gladstone, New York Times, "Contradicting Trump, U.N. Monitor Says Iran Complies With Nuclear Deal," 31 Aug. 2017
United Nations nuclear inspectors have said Iran worked to resolve the heavy water issues, has remained in compliance with centrifuge provisions and hasn’t intimidated inspectors.

— asa fitch, WSJ, "U.S. Officials Back Trump’s Stance on Iran Nuclear Accord," 15 Oct. 2017
In October 2016, Iran slightly surpassed a limit on its stockpiles of heavy water, which is used in medical imaging and can also fuel reactors that produce plutonium, a weapons material.

— kambiz foroohar, Bloomberg.com, "How Trump Can Oppose the Iran Deal But Not Quit It," 6 Oct. 2017

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

First Known Use of heavy water

1933

in the meaning defined at sense 1

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Medical Dictionary

heavy water

noun

medical Definition of heavy water

1 : the compound D₂O composed of deuterium and oxygen — called also deuterium oxide

2 : water having a higher-than-usual proportion of deuterium among its hydrogen atoms

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