tritium
Americannoun
noun
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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.
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See more at hydrogen
Etymology
Origin of tritium
1930–35; < New Latin < Greek trít ( os ) third ( tri- tri- + -tos adj. suffix) + New Latin -ium -ium
Vocabulary lists containing tritium
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Deuterium is abundant, but tritium is scarce because it is radioactive, with a half-life of only 12.3 years.
From The Wall Street Journal • Dec. 28, 2025
A fusion plant powering a single gigawatt data center would consume several times the world’s current tritium inventory each year.
From The Wall Street Journal • Dec. 28, 2025
KATRIN's exceptionally low background means that nearly all detected electrons originate from tritium decay, allowing for a very clean measurement of the energy spectrum.
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
After Washington, Lawrence and Alvarez planned to fly to Ottawa for a look at the Canadian government’s heavy-water reactor in nearby Chalk River, a design they thought might be adapted for tritium production.
From "Big Science" by Michael Hiltzik
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
