or Coal Sack
a dark nebula in the southern constellation Crux, whose dust particles obscure light from Milky Way stars behind it.
Origin of Coalsack
Also called Southern Coalsack.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a dark nebula in the Milky Way close to the Southern Cross
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012