tritium

American  

[trit-ee-uhm, trish-, trish-uhm] / ˈtrɪt i əm, ˈtrɪʃ-, ˈtrɪʃ əm /

noun

Chemistry.

1. an isotope of hydrogen having an atomic weight of three. 3 H, T

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tritium British  

/ ˈtrɪtɪəm /

noun

1. a radioactive isotope of hydrogen, occurring in trace amounts in natural hydrogen and produced in a nuclear reactor. Tritiated compounds are used as tracers. Symbol: T or ³H; half-life: 12.5 years

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tritium Scientific  

/ trĭt′ē-əm,trĭsh′ē-əm /

1. A radioactive isotope of hydrogen whose nucleus has one proton and two neutrons with atomic mass of about 3 and a half life of 12.5 years. Tritium is rare in nature but can be made artificially in nuclear reactions. It is used in thermonuclear weapons and luminescent paints, and sometimes as a tracer.

2. See more at hydrogen

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Etymology

Origin of tritium

1930–35; < New Latin < Greek trít ( os ) third ( tri- tri- + -tos adj. suffix) + New Latin -ium -ium

Example Sentences

See Examples For:

tritium

Specifically, from the decay of tritium, a form of hydrogen, inside those weapons.

From BBC ● Jun. 16, 2026

Any viable reactor must “breed” its own tritium by exposing a lithium blanket to the fusion-produced neutrons—a process not yet demonstrated at scale.

From The Wall Street Journal ● Dec. 28, 2025

It does this by carefully tracking the energies of electrons released during the β-decay of tritium.

From Science Daily ● Dec. 27, 2025

The state of Illinois sued Exelon after finding tritium in the water near one of its nuclear reactors.

From Barron's ● Oct. 17, 2025

Teller believed a promising option to fuel a Super bomb would be to use tritium, a superheavy isotope of hydrogen.

From "Big Science" by Michael Hiltzik