Supernovae are powerful stellar explosions that occur when a massive star dies. There are a few synonyms for the term supernovae, including stellar explosions, exploding stars, and supernova events. Other related terms include nova, which is a smaller explosion that occurs on the surface of a white dwarf star, as well as hypernova, which is an even more powerful type of supernova that occurs in very massive stars. These types of stellar explosions are important phenomena in astrophysics, providing insight into the nature of the universe and the life cycle of stars.