definitions

atomic mass unit

noun Physics.

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.
(formerly) a unit of mass, equal to 1/16 (0.0625) the mass of an oxygen atom having atomic mass 16. Abbreviation: amu, AMU

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Nearby words

atomic energy commission, atomic force microscope, atomic heat, atomic hydrogen, atomic mass, atomic mass unit, atomic number, atomic orbital, atomic pile, atomic power, atomic reactor

Origin of atomic mass unit

First recorded in 1950–55
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for atomic mass unit

atomic mass unit

noun

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 kgAbbreviation: 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

Medicine definitions for atomic mass unit

atomic mass unit

n.

A unit of mass equal to 112 the mass of an atom of carbon 12, which is assigned a mass of 12.dalton
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 unit

atomic mass unit

A unit of mass equal to 112 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 X 10-24 grams. A hydrogen atom has a mass of 1 atomic mass unit since its mass is 112 the mass of carbon 12. Also called dalton
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.