An Etymological Dictionary of Astronomy and Astrophysics

The energy (E) associated with a mass (m), as specified by the → mass-energy equivalence  E = mc², where c is the → speed of light. For a moving body the total energy of the particle is expressed by: E² = m²c⁴ + p²c², where m is → rest mass and p → momentum.

See also: → mass; → energy.