Mob-cap: a type of woman’s indoor cap, 1795 (as simply mob, 1748), from cap (n.) + obsolete mob (n.) “negligent attire” (1660s), earlier “a strumpet” (earlier form mab, 1550s), related to obsolete verb mob “to tousle the hair, to dress untidily” (1660s) - Online Etymology Dictionary
I found one of these delightful pieces in a shop in the Historic Downtown Pensacola area; if you have any tours or museums near you, pop in and see if they have one of these beauties lying around! Mob-caps came into fashion in the 18th century and were popular, at one time or another, for everyone from the most posh ladies to the poorest farm girl. There is even some evidence that they are the garment that led to the nylon caps modern nurses wear! If you’re interested in the couture interpretations, check out this girl’s lovely post.
Image is of Marie Antoinette, via Wikimedia Commons, and is in the Public Domain.