Megaelectron-volts
A megaelectron-volt (MeV) is a unit of energy used in particle and nuclear physics. It is derived from the electron-volt (eV) - the amount of kinetic energy gained or lost by an electron when it moves through one volt.
Calories (15 °C, NBS 1939)
The 15 °C NBS 1939 calorie is the amount of energy required to raise the temperature of one gram of water by one degree Celsius, from 14.5 °C to 15.5 °C, at standard atmospheric pressure. This specific definition was established by the National Bureau of Standards (NBS) in 1939.