tri·​ti·​um | \ ˈtri-tē-əm How to pronounce tritium (audio) , ˈtri-shē- \

Definition of tritium

: a radioactive isotope of hydrogen that has one proton and two neutrons in its nucleus and that has three times the mass of ordinary hydrogen symbol T

Examples of tritium in a Sentence

Recent Examples on the Web The tritium hypothesis fits the data to a confidence level of 3.2 sigma. Rafi Letzter, Scientific American, "Physicists Announce Potential Dark Matter Breakthrough," 17 June 2020 The isotopes butting heads will be deuterium and tritium. Laura Mallonee, Wired, "Fusion Energy Gets Ready to Shine—Finally," 21 Apr. 2020 Experts say tritium is not harmful to humans in small amounts and has been routinely released from nuclear plants around the world. Washington Post, "Japan revises Fukushima cleanup plan, delays key steps," 27 Dec. 2019 The experiment uses tritium (a highly radioactive isotope of hydrogen, with one proton and two neutrons) to generate electron-neutrino pairs: an electron and a neutrino that share 18,650 eV of energy between them. Jennifer Ouellette, Ars Technica, "Weighing in: Physicists cut upper limit on neutrino’s mass in half," 19 Sep. 2019 Government officials also say tritium is routinely released from existing nuclear power plants around the world. Fox News, "Japan advances plan to release Fukushima plant's radioactive water into the sea," 1 Feb. 2020 Replacing some of the deuterium with tritium, an even heavier isotope of hydrogen, could make the reactions self-sustaining. Adrian Cho, Science | AAAS, "After decades of decline, the U.S. national fusion lab seeks a rebirth," 6 Feb. 2020 The processing removes most of the radioactive elements except for tritium. Washington Post, "Why Japan’s Radioactive Water May End Up In the Ocean," 18 Oct. 2019 While the water has been treated to remove most of the most dangerous radioactive components, traces of tritium remain. NBC News, "Can Japan's 'Recovery Olympics' heal Fukushima's nuclear scars?," 13 Jan. 2020

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

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First Known Use of tritium

1933, in the meaning defined above

History and Etymology for tritium

New Latin, from Greek tritos third — more at third entry 1

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Time Traveler for tritium

Time Traveler

The first known use of tritium was in 1933

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Last Updated

27 Jun 2020

Cite this Entry

“Tritium.” Dictionary, Merriam-Webster, Accessed 7 Jul. 2020.

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tri·​ti·​um | \ ˈtrit-ē-əm How to pronounce tritium (audio) , ˈtrish-ē- How to pronounce tritium (audio) \

Medical Definition of tritium

: a radioactive isotope of hydrogen that has three times the mass of ordinary hydrogen symbol T

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