The magnetic quantum number refers to the orientation of an atomic orbital in a magnetic field. It is one of four quantum numbers used to describe the properties of electrons in an atom. There are several synonyms for magnetic quantum number: m quantum number, azimuthal quantum number, and orbital magnetic quantum number. The m quantum number indicates the number of orbitals within a subshell and its orientation in a magnetic field. The azimuthal quantum number describes the shape of the orbital, which is related to the angular momentum of the electron. The orbital magnetic quantum number gives the energy and orientation of an orbital in a magnetic field. All of these terms are used interchangeably to describe the same concept.