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The physical mass of a body as measured by an observer who perceives the body as motionless. Rest mass is an inherent property of elementary particles. Also called invariant mass.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
(General Physics) the mass of an object that is at rest relative to an observer. It is the mass used in Newtonian mechanics
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body in the theory of relativity.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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|Noun||1.||rest mass - (physics) the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body|
mass - the property of a body that causes it to have weight in a gravitational field
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