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[doo-teer-ee-uh m, dyoo-] /duˈtɪər i əm, dyu-/
noun, Chemistry.
an isotope of hydrogen, having twice the mass of ordinary hydrogen; heavy hydrogen. Symbol: D; atomic weight: 2.01; atomic number: 1.
Origin of deuterium
1933; < Greek deúter(os) second (see deutero-) + -ium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for deuterium
Contemporary Examples
Historical Examples
  • Well, heavy water is made of one atom of oxygen plus two atoms of deuterium, which is the first isotope of hydrogen.

    The Caves of Fear John Blaine
  • Then, for a considerably higher price, he would undertake to collect a sample of the deuterium they were using.

    The Caves of Fear John Blaine
British Dictionary definitions for deuterium


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
Word Origin
C20: New Latin; see deutero-, -ium; from the fact that it is the second heaviest hydrogen isotope
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for deuterium

1933, coined by U.S. chemist Harold C. Urey, with Modern Latin ending + Greek deuterion, neuter of deuterios "having second place," from deuteros "second," from duo (see two). So called because it is twice the mass of hydrogen.

Online Etymology Dictionary, © 2010 Douglas Harper
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deuterium in Medicine

deuterium deu·te·ri·um (dōō-tēr'ē-əm, dyōō-)
An isotope of hydrogen with one proton and one neutron in the nucleus having an atomic weight of 2.014. Also called heavy hydrogen, hydrogen-2.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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deuterium in Science
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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