noun
: the tendency of matter to move toward a common center of gravity (as in the formation of galaxies) ; especially : the rapid collapse of a star at the end of its life cycle
noun
: the tendency of matter to move toward a common center of gravity (as in the formation of galaxies) ; especially : the rapid collapse of a star at the end of its life cycle
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012