What is another term for the thickness of a sleeping bag?

The term that best describes the thickness of a sleeping bag is "loft." Loft refers to the amount of space a sleeping bag fills when it is fully expanded and indicates how fluffy the bag is. This thickness plays a crucial role in insulation as it traps air, which helps retain body heat. A higher loft generally means better insulating properties and warmth.

While volume refers to the space occupied, it doesn’t specifically capture the idea of insulation that loft represents. Density relates to the mass of the material per unit of volume, which is not the same as measuring thickness or the ability to provide warmth. Warmth, on the other hand, is an effect of loft but does not directly describe the physical attribute of thickness that loft conveys. Thus, loft is the most accurate term connected to the concept of thickness in the context of sleeping bags.