rest energy
Noun
Meaning
the energy equivalent to the mass of a particle at rest in an inertial frame of reference; equal to the rest mass times the square of the speed of light
Source: WordNetHypernyms
Examples
A rest energy can be calculated even for particles and systems in motion, by translating to a frame in which momentum is zero.
An analysis of the doubly differential cross section above shows that electrons whose kinetic energy is larger than the rest energy (511 keV) emit photons in forward direction while electrons with a small energy emit photons isotropically.
In the rest frame of an object, it has a rest energy and zero momentum.
Wave energies (such as radiant or sound energy), kinetic energy, and rest energy are each greater than or equal to zero because they are measured in comparison to a base state of zero energy: "no wave", "no motion", and "no inertia", respectively.