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

The United States currently uses the civilian reactors of the Tennessee Valley Authority to make tritium for hydrogen bombs. —Thomas Bass author, Newsweek, 19 Dec. 2024

The most reliable source of tritium is a fission reactor, which somewhat defeats the purpose of using fusion. —Bayarbadrakh Baramsai, IEEE Spectrum, 27 Feb. 2022

And there are three slots for tritium vials to help users find the UltraFix Driver easier in the dark. —Paul Ridden, New Atlas, 24 Dec. 2024

Rounding out the multitool's features are three slots for optional glow-in-the-dark vials of tritium, to help find the thing at night or in a coal mine. —Ben Coxworth, New Atlas, 13 Dec. 2024

Word History

Etymology

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

First Known Use

1933, in the meaning defined above

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