Meaning of Cygnus X-1

Cygnus X-1

Pronunciation: (eks'wun'), [key]
— Astron. Astron.
  1. a strong x-ray source in the constellation Cygnus, consisting of a binary system of which one component may be a black hole.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.