We propose a new interpretation of the equation E=mc(2) in special relativity by generalizing ideas of ontological emergence to fundamental physics. This allows us to propose that mass, as a property, can be considered to emerge from energy, using a well-known definition of weak ontological emergence. Einstein's famous equation gains in this way a clearer philosophical interpretation, one that avoids the problems of previous attempts, and is fully consistent with the kinematic properties of special relativity, while yielding fresh insights concerning the nature of mass.