Atomic X-rays and nuclear gamma rays are distinguished by their origins; X-rays result from interactions with electrons, such as bremsstrahlung or inner orbital electron ejection, while gamma rays are produced by nuclear de-excitations or subatomic processes like antimatter reactions. There is no clear boundary between X-rays and gamma rays, as both are high-energy photons but stem from different physical processes. The term "photoelectric" does not apply as a common process for both emissions. Additionally, bound electrons do not generate gamma rays. Understanding these distinctions is crucial for accurately categorizing high-energy photon emissions.