A male one-piece (or later, two-piece) undergarment that covers both the upper and lower torso. Originally called a union suit because the top and bottom were united as a one-piece garment. Originally made with ankle length legs and long sleeves. Later available in knee length versions with or without sleeves. Usually buttoned down the front with a drop seat in the latter 19th century. Available in many varying designs of crotch closure for convenience and hygiene in the first half of the 20th century.