conservation of energy(redirected from Conservation of mass-energy)
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con·ser·va·tion of en·er·gy
the principle that the total amount of energy in a closed system remains always the same, none being lost or created in any chemical or physical process or in the conversion of one kind of energy into another, within that system.
conservation of energy
The principle according to which energy cannot be created or destroyed, but is transformed into other forms.
See also: energy