a rare, extremely bright nova that suddenly increases up to a billion times in brightness and reaches an absolute magnitude of c. -16
See supernova in American Heritage Dictionary 4
su·per·no·va
nounpl.supernovaesu·per·no·vae(-vē) or su·per·no·vas
A rare celestial phenomenon involving the explosion of most of the material in a star, resulting in an extremely bright, short-lived object that emits vast amounts of energy.