atomic masses

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 the mass of one oxygen atom, but after 1961 based on 1 / 12 the mass of the carbon-12 atom. Abbreviation: at. m.
Origin:
1895–1900

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Based on the Random House Dictionary, © Random House, Inc. 2013.
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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
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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00:10
Atomic masses is always a great word to know.
So is ort. Does it mean:
a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.
a scrap or morsel of food left at a meal.
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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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