plus fours
Plus fours are breeches or trousers that extend four inches (10 cm) below the knee (and thus four inches longer than traditional knickerbockers, hence the name). Knickerbockers have been traditionally associated with sporting attire since the 1860s. Plus fours were introduced in the 1920s and became popular among sportsmen—particularly golfers and game shooters—as they allowed more freedom of movement than knickerbockers.