The term is short for Kinetic Energy Released per Unit Mass (although many refer to the term 'Kinetic Energy Released in Material'). Either term can mean the same thing although by definition the former term is more accurate since the quantity is based on functions of energy and mass. KERMA is a quantity which expresses the initial kinetic energy of all charged Ionising Radiations (e.g. photo-electrons) which are produced as a result of indirectly ionising radiations (e.g. Photons) interaction with material. The quantity is material specific (e.g. air-KERMA or water-KERMA) and has the units J/kg or Gray. KERMA is related to Absorbed Dose but is not the same quantity.