dark star

Short definition from Wiktionary

Noun

1. 1
   An extremely bright and massive hypothetical astrophysical object whose illumination is powered by annihilation of dark-matter particles and anti-particles (or by self-annihilation if they are Majorana particles).
2. 2
   A black hole: star so massive that its escape velocity is above the speed of light, making the star dark, as no light can escape.
3. 3
   Used other than figuratively or idiomatically: see dark, star.