deuterium
Americannoun
-
an isotope of hydrogen, having twice the mass of ordinary hydrogen; heavy hydrogen. 2 H, D; 2.01; 1.
noun
-
a stable isotope of hydrogen, occurring in natural hydrogen (156 parts per million) and in heavy water: used as a tracer in chemistry and biology. Symbol: D or ²H; atomic no: 1; atomic wt: 2.014; boiling pt: –249.7°C
-
An isotope of hydrogen whose nucleus has one proton and one neutron and whose atomic mass is 2. Deuterium is used widely as a tracer for analyzing chemical reactions, and it combines with oxygen to form heavy water.
-
Also called heavy hydrogen
-
See Note at heavy water
Etymology
Origin of deuterium
Compare meaning
How does deuterium compare to similar and commonly confused words? Explore the most common comparisons:
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.
First-generation reactors will almost certainly be fueled by the hydrogen isotopes deuterium and tritium.
From The Wall Street Journal • Dec. 28, 2025
A good thing to note is that deuterium, a stable isotope of hydrogen, is much less expensive and can be found in seawater.
From Los Angeles Times • Sep. 15, 2024
Cancerous cells exhibited a similar but not quite as strong shortage in deuterium.
From Science Daily • May 6, 2024
The facility will generate neutrons by focusing an intense beam of deuterium nuclei on a lithium target.
From Science Magazine • Oct. 11, 2023
The neutron and deuterium were both discoveries from that miraculous year of 1932, when nuclear physics gave up some of its greatest secrets.
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.