A Boudoir Cap (Lingerie Cap, Morning Cap) is a flat bandeau cap usually made of satin, lace, and ribbon. They were very popular in the 1920s and were often made at home from kits.
Traditionally, a nightcap was a piece of cloth worn while sleeping to keep the head warm. Women typically wore rounded, brimless versions while men wore a more pointy crown style. They evolved to become more fashionable and were no longer used for warmth.Written by LadyScarletts and TheVintageFashionGuild