A roadster (spider or spyder) is an open two-seat car with emphasis on sporting appearance or character. Initially an American term for a two-seat car with no weather protection, usage has spread internationally and has evolved to include two-seat convertibles. The roadster was also a style of racing car driven in United States Auto Club (USAC) Championship Racing, including the Indianapolis 500, in the 1950s and 1960s. This type of racing car was superseded by mid-engined cars.