A shirt, button shirt, dress shirt, button-front, button-front shirt, button-down, button-down shirt, or button-up shirt is a garment with a collar, and a full-length opening at the front from the collar to the hem.
The front opening is fastened using buttons or studs. Shirts are normally made from woven cloth, and are often accompanied by a jacket, collar sleeve, and tie, for example with a suit or formalwear, but shirts are also worn more casually.
In British English, dress shirt means specifically the more formal evening garment worn with black- or white- tie, also discussed below. Some of these formal shirts have stiff fronts and detachable collars attached with collar studs.
Traditionally dress shirts were worn by men and boys (while women and girls often wore blouses or, sometimes, chemises), but in the mid-1800s they also became an item of women's clothing and are worn by both sexes today.
The term "button-down" refers a type of shirt which has a collar fastened down by buttons,) but is sometimes used in error to apply to all dress shirts.