deuterium
noun
deu·te·ri·um
dü-ˈtir-ē-əm 
also dyü-
: an isotope of hydrogen that has one proton and one neutron in its nucleus and that has twice the mass of ordinary hydrogen
—symbol D
called also heavy hydrogen
Examples of deuterium in a Sentence
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Both use different approaches to achieve a promising form of nuclear fusion called magnetic confinement, which aims to ignite a fusion reaction in a plasma of the neutron-heavy hydrogen isotopes deuterium and tritium.
—
Tom Metcalfe, Scientific American, 2 July 2025
Building a fusion reactor Fusion occurs when two types of hydrogen atoms, deuterium and tritium, collide in extreme conditions.
—Farhat Beg, The Conversation, 8 Jan. 2025
When lasers hit the outside of this capsule, their energy is converted into X-rays that then blast the fuel pellet, which consists of a diamond outer shell coated on the inside with deuterium and tritium fuel.
—IEEE Spectrum, 6 Feb. 2024
On Earth, scientists are aiming to fuse deuterium and tritium—both isotopes, or versions, of hydrogen.
—Margherita Bassi, Smithsonian Magazine, 18 Apr. 2025
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Tom Metcalfe, Scientific American, 2 July 2025
Building a fusion reactor Fusion occurs when two types of hydrogen atoms, deuterium and tritium, collide in extreme conditions.
—Farhat Beg, The Conversation, 8 Jan. 2025
When lasers hit the outside of this capsule, their energy is converted into X-rays that then blast the fuel pellet, which consists of a diamond outer shell coated on the inside with deuterium and tritium fuel.
—IEEE Spectrum, 6 Feb. 2024
On Earth, scientists are aiming to fuse deuterium and tritium—both isotopes, or versions, of hydrogen.
—Margherita Bassi, Smithsonian Magazine, 18 Apr. 2025
See All Example Sentences for deuterium
Cite this Entry
“Deuterium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/deuterium. Accessed 19 Jul. 2025.
Copy CitationKids Definition
deuterium
noun
deu·te·ri·um
d(y)ü-ˈtir-ē-əm
: the hydrogen isotope that is twice the mass of ordinary hydrogen
called also heavy hydrogen
Medical Definition
deuterium
noun
deu·te·ri·um
d(y)ü-ˈtir-ē-əm
: an isotope of hydrogen that has one proton and one neutron in its nucleus and that has twice the mass of ordinary hydrogen
called also heavy hydrogen
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