Plus-fours are breeches or trousers that extend 4 inches (10 cm) below the knee (and thus four inches longer than traditional knickerbockers, hence the name). As they allow more freedom of movement than knickerbockers, they have been traditionally associated with sporting attire from the 1860s and onward, and are also particularly associated with golf.
An "extravagant, careless style that fit right in with the looser fashions and lifestyles of the 1920s," plus-fours were introduced to America by Edward, Prince of Wales (later Edward VIII), during a diplomatic trip in 1924. They are often seen on golf courses, and frequently worn with argyle socks, silk neckties, and dress shirts or sweaters. Some plus fours came as complete suits. They became associated with bicycle fashion in the 1950s and 60s in Great Britain.
They were later brought back to prominence by the professional golfer Payne Stewart who wore them on the PGA Tour.
In 2008, plus-fours were featured in André Benjamin's Benjamin Bixby clothing line, which was based on clothing worn by Ivy League athletes in the 1930s.
Less known are plus-twos, plus-sixes, and plus-eights, of similar definitions.
In fiction, Tintin, the comic book character from The Adventures of Tintin, famously wears plus-fours.