mass-energy

plural mass-energies

1. countableuncountablenatural sciencesMass and energy as a unified concept.

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

   2 more examples

   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).

2. countableuncountablealso spelled mass energyThe energy associated with any given mass according to special relativity, E = mc².

1. not comparablemass-to-energy

   Mass-energy conversion occurs during nuclear fusion and fission.