Button down

A dress shirt, button shirt, button-front, button-front shirt, or button-up shirt is a garment with a collar and a full-length opening at the front, which is fastened using buttons or shirt studs. A button-down or button-down shirt is a dress shirt which has a button-down collar – a collar having the ends fastened to the shirt with buttons.

Dress 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" ("formal shirts," or "tuxedo shirts" in American English) means specifically the more formal evening garment worn with black- or white-tie. Some of these formal shirts have stiff fronts and detachable collars attached with collar studs.

Traditionally dress shirts were worn by men and boys, whereas women and girls often wore blouses or, sometimes, known as chemises. However, in the mid-1800s, they also became an item of women's clothing and are worn by both sexes today.

A shirt has several components: A one-piece back, which is usually pleated, gathered, or eased into a section of fabric in the upper part of the back behind the neck and over the shoulders known as the yoke (either one-piece or seamed vertically in the middle); one-piece sleeves with plackets at the wrist, or else short-sleeved (cut off above the elbow), though this is not traditional; a band of fabric around each wrist known as a cuff; the collar, a strip around the neck, which is normally a turndown collar, with the strip folded down away from the neck, leaving two points at the front, the width of which is known as the spread; and finally two front panels which overlap slightly down the middle on the placket to fasten with buttons (or rarely shirt studs).

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Wikipedia