A justacorps or justaucorps (⫽ˈʒuːstəkɔːr⫽)[1] is a knee-length coat worn by men in the latter half of the 17th century and throughout the 18th century. It is of French origin, and was introduced in England as a component of a three-piece ensemble, which also included breeches and a long vest or waistcoat. This ensemble served as the prototype of the frock coat, which in turn evolved into the modern-day three-piece suit.[2] The fabric selection and styling of the justacorps varied over time, as fashions altered through history.