The nuclear shell model is a theoretical framework used to explain the structure of atomic nuclei. It is a mathematical model that describes the distribution of mass and charge within a nucleus, based on the idea that the protons and neutrons in a nucleus arrange themselves into shells, much like the electrons in an atom. While there are no exact synonyms for the nuclear shell model, alternate terms such as nuclear structure theory, nuclear physics, and nuclear spectroscopy all refer to the study of the properties and behavior of nuclei, including the application of the shell model. These various terms all fall under the umbrella of nuclear science, a branch of physics that explores the properties and behavior of atomic nuclei.