Crab Nebula n (Astronomy) the expanding remnant of the supernova observed in 1054 ad, lying in the constellation Taurus at an approximate distance of 6500 light years Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014Crab? Neb`ula n. the remnant of a supernova explosion observed in 1054 A.D. in the constellation Taurus. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.