The concepts of rest mass and relativistic mass are considered outdated. In modern physics, "mass" means what they meant by "rest mass". Here some indication I

The concepts of rest mass and relativistic mass are considered outdated. In modern physics, "mass" means what they meant by "rest mass". Here some indication I'm not making this up: https://hsm.stackexchange.com/questions/2465/when-and-why-did-the-concept-of-relativistic-mass-become-outdated https://hsm.stackexchange.com/questions/2465/when-and-why-di... In any case, I never use those concepts, and I know no professional particle physicist that does. By "mass", I mean rest mass.