Science, Tech, Math › Science Nuclide Definition Share Flipboard Email Print Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry in Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate by Anne Marie Helmenstine, Ph.D. Updated March 06, 2017 Definition: Nuclides are an atom or ion characterized by the contents of their nucleus. Examples: 12C6 and 14C6 are both nuclides. Continue Reading