Definitions for "Supermassive black hole"
a black hole with a mass in the range of millions or billions of solar masses
Black holes that have the mass of 10 to 100 billion Suns. They are found in the centers of galaxies called active galactic nuclei, which are incredibly energetic.
A black hole that has a million or as much as a billion solar masses. Such huge black holes lurk at the centers of many active galaxies.