rest mass

American  

noun

Physics.

1. the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body.

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rest mass British  

noun

1. the mass of an object that is at rest relative to an observer. It is the mass used in Newtonian mechanics

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rest mass Scientific  

1. In Special and General Relativity, the observed mass of a body that is not in motion with respect to the observer.

2. Also called invariant mass

3. Compare relativistic mass

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Etymology

Origin of rest mass

First recorded in 1910–15

Example Sentences

Yesterday we found many new glaciers and two new inlets not down on the largest maps.

From My Boyhood by Burroughs, John