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atomic mass unit

noun, Physics.
1.
Also called dalton. a unit of mass, equal to 1/12 (0.0833) the mass of the carbon-12 atom and used to express the mass of atomic and subatomic particles.
2.
(formerly) a unit of mass, equal to 1/16 (0.0625) the mass of an oxygen atom having atomic mass 16.
Abbreviation: amu, AMU.
Origin
1950-1955
1950-55
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for atomic mass unit

atomic mass unit

noun
1.
a unit of mass used to express atomic and molecular weights that is equal to one twelfth of the mass of an atom of carbon-12. It is equivalent to 1.66 × 10–27 kg amu Also called unified atomic mass unit, dalton
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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atomic mass unit in Medicine

atomic mass unit n.
Abbr. amu
A unit of mass equal to 1/12 the mass of an atom of carbon 12, which is assigned a mass of 12. Also called dalton.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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atomic mass unit in Science
atomic mass unit  
A unit of mass equal to 1/12 the mass of an atom of the most common isotope of carbon (carbon 12), which is assigned a mass of 12 and has a value of 1.660 × 10-24 grams. A hydrogen atom has a mass of 1 atomic mass unit since its mass is 1/12 the mass of carbon 12. Also called dalton.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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10
12
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