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

Oh yes, and there are also the usual slots – three, in this case – for optional vials of glow-in-the-dark tritium. —Ben Coxworth, New Atlas, 16 Jan. 2025

This might entail surrounding the fusion reactor with lithium-containing material, which the reaction will convert into tritium. —Farhat Beg, The Conversation, 8 Jan. 2025

This core component contains a gas such as deuterium and tritium that is encased in chemical explosives. —Andrew Paul, Popular Science, 9 Jan. 2025

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

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