Meaning of mass-energy equation

mass'-en'er•gy equa"tion

Pronunciation: (mas'en'ur-jē), [key]
— Physics. Physics.
  1. the equation, E=mc, formulated by Albert Einstein, expressing the equivalence between mass and energy, where E is energy, m is mass, and c is the velocity of light.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.