nuclide nu·clide (nōō'klīd', nyōō'-)
A type of atom specified by its atomic number, atomic mass, and energy state, such as carbon 14.
An atomic nucleus identified by its atomic element and its mass number. For example, a carbon-14 nuclide is the nucleus of a carbon atom, which has six protons, with mass number 14 (thus having eight neutrons). See also isotope.