Waistcoat
A sleeveless, usually waist-length garment worn over a shirt and beneath a jacket, commonly fastened down the front.
Single-breasted: A garment fastening with one row of buttons and a front overlap that does not cross the body. Most waistcoats use this front fastening, with buttons running down the center.
Suit vest: A sleeveless garment worn with a suit, especially in American English. It is the closest name for the same garment in American clothing terminology.
Charles II of England: King of England, Scotland, and Ireland from 1660 until his death in 1685. In 1666, he announced a court dress featuring a long vest-like garment often linked to the waistcoat's history.
Black tie: A formal evening dress code centered on a dinner jacket and bow tie. A black waistcoat is one traditional alternative to a cummerbund with a dinner jacket.
Double-breasted: A garment with overlapping front panels and two parallel rows of buttons. This less common waistcoat front overlaps more deeply than the usual single row.
Jacket: A garment for the upper body, typically with sleeves and an opening at the front. Unlike a waistcoat, a jacket is usually the outer layer and has sleeves.
Justaucorps: A long, fitted coat worn by men in Europe from the seventeenth century onward. The waistcoat developed as a layer worn beneath this long coat.
White tie: The most formal evening dress code, featuring a tailcoat, white bow tie, and white waistcoat. Its prescribed waistcoat is a central visible element of the white-tie ensemble.
Welt pocket: A pocket opening finished with a narrow strip of fabric along its edge. Waistcoats often use welt pockets to keep the front relatively flat.
Gilet: A sleeveless upper-body garment, often padded or quilted and worn as outerwear. A gilet shares the sleeveless form but is generally designed as an outer layer.