A suit is a set of men's or women's clothes comprising a suit jacket, or coat, and trousers. When of identical textile, and worn with a collared dress shirt, necktie, and dress shoes, it was traditionally considered informal wear in Western dress codes. The lounge suit originated in 19th-century Britain as more casual wear alternative for sportswear and British country clothing. After replacing the black frock coat in the early 20th century as regular daywear, a sober one-coloured suit became known as a lounge suit. A darker, understated lounge suit for professional occasions became known as a business suit.
Suits are offered in different designs and constructions. Cut, and cloth, whether two- or three-piece, single- or double-breasted, vary, in addition to various accessories. A two-piece suit has a jacket and trousers, a three-piece suit adds a waistcoat. Hats were almost always worn outdoors with all men's clothes until the counterculture of the 1960s in Western culture. Informal suits have been traditionally worn with a fedora, a trilby, or a flat cap. Other accessories include handkerchief, suspenders or belt, watch, and jewelry.