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[proh-tee-uh m, -shee-uh m] /ˈproʊ ti əm, -ʃi əm/
noun, Chemistry
the lightest and most common isotope of hydrogen. Symbol: H 1.
1930-35; prot- + -ium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for protium


the most common isotope of hydrogen, having a mass number of 1
Word Origin
C20: New Latin, from proto- + -ium
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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protium in Medicine

protium pro·ti·um (prō'tē-əm, prō'shē-)
See hydrogen-1.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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protium in Science
  (prō'tē-əm, -shē-əm)   
The most abundant isotope of hydrogen, having an atomic mass of 1. Its nucleus consists of a single proton. See more at hydrogen.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for protium

isotope of hydrogen (q.v.) with atomic weight of approximately 1; its nucleus consists of only one proton. Ordinary hydrogen is made up almost entirely of protium.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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