A nuclear isomer is a type of atom that has the same number of protons and electrons as a regular atom, but it has a different number of neutrons in its nucleus. This difference in the number of neutrons leads to a different energy state, and the atom is said to be in an isomeric state. There are several synonyms for nuclear isomer that are commonly used in scientific literature, including nuclear metastable state, nuclear excited state, and nuclear excited isomer. Other related terms include nuclear isotope, nuclear radiation, and nuclear decay. Understanding the different terminology associated with nuclear isomers is essential for scientists studying nuclear physics and related fields.