From Longman Dictionary of Contemporary Englishsleeping bagˈsleeping bag noun [countable] 
DLOa large warm bag that you sleep in, especially when camping
DLOa large warm bag that you sleep in, especially when campingExamples from the Corpus
sleeping bag• She fitted out the summerhouse with a sleeping bag and a change of jeans.• The drawcords on the fleece and the Merlin sleeping bag pull in freely and close tightly if required.• Stewart had purchased a serviceable sleeping bag and managed quite well, but several mates suffered frostbite; some required hospitalization. 