Coalsack: Meaning and Definition of

Coal•sack

Pronunciation: (kōl'sak"), [key]
— n. Astron.
  1. a dark nebula in the southern constellation Crux, whose dust particles obscure light from Milky Way stars behind it. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.