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.
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Nearby words
Origin of atomic mass
First recorded in 1895–1900
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for atomic mass
atomic mass
noun chem
the mass of an isotope of an element in atomic mass units
short for relative atomic mass See atomic weight
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Medicine definitions for atomic mass
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.
Science definitions for atomic mass
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 © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.