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

Unlike nuclear fission – which splits atoms and creates dangerous radioactive waste – fusion uses hydrogen isotopes (like tritium and deuterium) and produces helium as a harmless byproduct. —New Atlas, 22 Dec. 2024

But ramping up the production of tritium, which is usually produced from lithium, will prove far more difficult. —Farhat Beg, The Conversation, 8 Jan. 2025

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

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