A breeches role is a part in an opera in which a woman plays the role of a man. It is also called a trouser role (British) or pants role (U.S.) or travesti role (the Italian word). It is called a breeches role because breeches are tight-fitting, knee-length trousers. These used to be worn by men at the time that breeches roles became popular. Sometimes breeches roles are in plays, but they are usually in opera.