A ground-effect vehicle (GEV), also called a wing-in-ground-effect (WIGE or WIG), ground-effect craft/machine (GEM), wingship, flarecraft, surface effect vehicle or ekranoplan (Russian: экранопла́н – "screenglider"), is a vehicle that makes use of the ground effect, the aerodynamic interaction between a moving wing and the stationary surface below (land or water). Typically, it glides over a level surface (usually over water). Some models can operate over any flat area such as a lake or flat plains similar to a hovercraft. The term Ground-Effect Vehicle originally referred to any craft utilizing ground effect, including what later became known as hovercraft, in patent descriptions during the 1950s. However, this term came to exclude air-cushion vehicles or hovercraft. GEVs do not include racecars utilizing ground-effect for increasing downforce.