a snug-fitting sleeping bag tapered from the shoulders to the feet, enclosing both the body and head except for a small opening for the face.
Origin of mummy bag
so called because its shape resembles a wrapped Egyptian mummy
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a sleeping bag with a hood
Word Origin for mummy bag
C20: so called because the wearer resembles a mummified body
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