deuterium

noun deu·te·ri·um \ dü-ˈtir-ē-əm also dyü- \

Updated on: 22 Apr 2018

Definition of deuterium

: 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

See deuterium defined for kids

Recent Examples of deuterium from the Web

In any case, the reason to differentiate them isn't burning deuterium.

— sophie weiner, Popular Mechanics, "Are Brown Dwarfs Planets or Failed Stars?," 24 Mar. 2018
The nuclear fuel used in the Alcator C-Mod previously contained just two types of ions, deuterium and hydrogen.

— jay bennett, Popular Mechanics, "MIT Achieves Breakthrough in Nuclear Fusion," 28 Aug. 2017
The excited hydrogen ions then slam into the more abundant deuterium ions, and resulting particles fly into the reactor's outer shell, generating heat and electricity.

— jay bennett, Popular Mechanics, "MIT Achieves Breakthrough in Nuclear Fusion," 28 Aug. 2017
To make a hydrogen bomb, one would still need uranium or plutonium as well as two other isotopes of hydrogen, called deuterium and tritium.

— melissa chan, Time, "What Is the Difference Between a Hydrogen Bomb and an Atomic Bomb?," 22 Sep. 2017
Below 80 Jupiter masses, star-like objects are called brown dwarfs and only fuse hydrogen into the isotope deuterium.

— john wenz, Popular Mechanics, "This Is the Smallest Star Ever Discovered," 11 July 2017
The fusion reactors that Princeton Satellite Systems is developing uses low-frequency radio waves to heat a mix of deuterium and helium-3, and magnetic fields to confine the resulting plasma in a ring.

— NBC News, "Are These Little Rockets the Future of Spaceflight?," 13 June 2017
The fuels were deuterium and tritium, rare forms of hydrogen.

— william j. broad, New York Times, "U.S. Nuclear History Offers Clues to North Korea’s Progress," 22 May 2017
Deuterium, which is an isotope of hydrogen, has a neutron in its nucleus.

— National Geographic, "Inside the Daring Mission That Thwarted a Nazi Atomic Bomb," 5 June 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'deuterium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of deuterium

New Latin, from Greek deuteros second

NEW! Time Traveler

First Known Use: 1933

See Words from the same year

Medical Dictionary

deuterium

noun deu·te·ri·um \ d(y)ü-ˈtir-ē-əm \

medical Definition of deuterium

: 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