rest mass
noun Physics.
the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body.
Compare
relativistic mass.
Origin of rest mass
First recorded in 1910–15
Words nearby rest mass
rest area,
rest assured,
rest cure,
rest energy,
rest home,
rest mass,
rest on one's laurels,
rest room,
rest stop,
rest-cure,
rest-home
British Dictionary definitions for rest mass
rest mass
noun
the mass of an object that is at rest relative to an observer. It is the mass used in Newtonian mechanics
Medical definitions for rest mass
rest mass
n.
The physical mass of a body when it is regarded as being at rest.
Scientific definitions for rest mass
rest mass
In Special and General Relativity, the observed mass of a body that is not in motion with respect to the observer. Also called invariant mass Compare relativistic mass.