mass-energy

mass-energy (countable and uncountable, plural mass-energies)

1. (physics) Mass and energy as a unified concept.

   Whereas in classical physics mass and energy are distinct concepts, on relativistic scales, they become indistinguishable and are replaced by mass-energy.

   In higher-energy physics, mass and energy eventually become meaningless as individual concepts; a particle's so-called "mass" is actually mass-energy and is often given equivalently in units of either mass (GeV/c²) or energy (GeV).

   For equations normalized with Planck units, the quantities of mass and energy become numerically identical, revealing their true nature as mass-energy.

2. (also spelled mass energy) The energy associated with any given mass according to special relativity, E = mc².

• Einstein energy
• relativistic mass

mass-energy (not comparable)

1. mass-to-energy

   Mass-energy conversion occurs during nuclear fusion and fission.