Fission reaction is a chemical process in which a nucleus of a heavy element splits into two or more smaller nuclei. There are several synonyms for fission reaction, such as nuclear fission, radioactivity, atomic splitting, and atomic disintegration. These terms describe the same process of breaking apart the nucleus of an atom, which releases energy in the form of radioactive particles and electromagnetic waves. Fission reaction is the basis of nuclear power generation and atomic bombs, and it is a crucial topic in physics and chemistry. By understanding the synonyms of fission reaction, we can gain a better appreciation of the complexity and importance of this fundamental process.