The term chemise can refer to the classic smock or shift, or else can refer to certain modern types of women's undergarments and dresses. In the classical usage it is a simple garment worn next to the skin to protect clothing from sweat and body oils, the precursor to the modern shirts commonly worn in Western nations.
Chemise is a French term (which today simply means shirt). This is a cognate of the Italian word camicia, and the Spanish / Portuguese word camisa (subsequently borrowed as kameez by Hindi / Urdu / Hindustani), all deriving ultimately from the Latin camisia. The English called the same shirt a smock and the Irish called it a léine (). For an alternative etymology from Farsi via Arabic and ultimately Greek, rather than Latin roots, refer entry under Kameez.
The chemise seems to have been developed from the Roman tunica and first became popular in the European Middle Ages. Women wore shifts or chemises underneath their gowns or robes; men wore chemises with their trousers or braies, and covered the chemises with garments such as doublets, robes, etc. In those times, it was usually the only piece of clothing that was washed regularly. In Western countries, women's shirts did not fall out of fashion until the early 20th century, when they were generally replaced by brassieres, panties, girdles, and full slips.
Men's chemises may be said to survive as the common T-shirt, which still serves as an undergarment. The chemise also morphed into the smock-frock, a garment worn by English laborers until the early 20th century. Its loose cut and wide sleeves were well adapted to heavy labor. The name smock is nowadays still used for military combat jackets in the UK, whereas in the Belgian army the term has been corrupted to smoke-vest. '''
A chemise, shift, or smock was usually sewn at home, by the women of a household. It was assembled from rectangles and triangles cut from one piece of cloth so as to leave no waste. The poor would wear skimpy chemises pieced from a narrow piece of rough cloth; the rich might have voluminous chemises pieced from thin, smooth fine linen.
There is a similar type of lingerie/sleepwear known as the babydoll. Both terms describe short, loose-fitting, sleeveless fashions. Typically, though, babydolls are more loose-fitting at the hips and are generally designed to more resemble a young girl's nightgown (although many modern varieties only vaguely follow this definition adding various sexualizing features which, of course, would only be appropriate for an adult).