atomic-mass

atomic mass

noun Chemistry.
the mass of an isotope of an element measured in units formerly based on the mass of one hydrogen atom taken as a unit or on 1/16 (0.0625) the mass of one oxygen atom, but after 1961 based on 1/12 (0.0833) the mass of the carbon-12 atom. Abbreviation: at. m.

Origin:
1895–1900

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Collins
World English Dictionary
atomic mass
 
n
1.  the mass of an isotope of an element in atomic mass units
2.  short for relative atomic mass See atomic weight

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Medical Dictionary

atomic mass n.
The mass of an atom, usually expressed in atomic mass units.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
atomic mass  
The mass of a given atom or molecule, expressed in atomic mass units. Compare atomic weight. See also mass number.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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