Definitions
There is 1 meaning of the phrase
Rest Mass.
Rest Mass - as a 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
Example Sentences
"The rest mass of the electron is approximately 9.1 x 10^-31 kilograms."
"According to Einstein's theory of relativity, rest mass is a fundamental property of matter."
"The rest mass of a photon is always zero."
"Particles with non-zero rest mass are called massive particles."
"The rest mass of a particle determines its energy and momentum."