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

Origin of atomic mass unit

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

British Dictionary definitions for atomic mass unit

atomic mass unit


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

atomic mass unit in Medicine

atomic mass unit


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.

atomic mass unit in Science

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.