tritium

noun

tri·ti·um ˈtri-tē-əm ˈtri-shē-

: 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

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.

The company says its Infinity Two design is based on a deuterium-tritium fusion reaction and is designed to produce 800 megawatts of fusion power, with 400 megawatts delivered to the electrical grid. — Neetika Walter, Interesting Engineering, 31 Aug. 2026 Six tritium tube slots around the bit storage are designed to improve visibility in dark conditions. — Maryna Holovnova, New Atlas, 28 Aug. 2026 Moreover, tritium is easier to produce than plutonium, which has to be created in a costly and complex technological process that involves the irradiation of uranium in a nuclear reactor. — Tereza Pultarova, IEEE Spectrum, 10 Aug. 2026 See All Example Sentences for tritium

Word History

Etymology

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

First Known Use

1933, in the meaning defined above

Time Traveler

The first known use of tritium was in 1933

See more words from the same year

Browse Nearby Words

tritish

tritium

trito-

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Cite this Entry

Style

“Tritium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tritium. Accessed 3 Sep. 2026.

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Kids Definition

tritium

noun

tri·ti·um ˈtrit-ē-əm ˈtrish-ē-

: a rare radioactive form of hydrogen having atoms with three times the mass of ordinary light hydrogen atoms

Medical Definition

tritium

noun

tri·ti·um ˈtrit-ē-əm ˈtrish-ē-

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

—symbol T

tritium

noun

Examples of tritium in a Sentence

Word History

Browse Nearby Words

Cite this Entry

Kids Definition

Medical Definition

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