Swim trunks, also known as swimming trunks, are a form of swimsuit worn by men and boys specifically for swimming. As such, they are typically made of materials designed for being wet and remaining comfortable and hydrodynamic to not impede the swimmer. The choice of materials makes them distinct from underwear which may have a similar shape. The term is a catch-all for a number of styles of garment such as briefs, shorts and "jammers".