A bit of history... Back in the day when horse_less carriages were in their infancy, it did not take long before the competitive or "sporting" aspect of drivers came to roost...
In Britain, horse_less carriage races were banned from their well groomed oval horse race tracks which moved horse_less carriage races on to roads... This is the origins of road racing in Europe..
In America where horse race tracks were less precious, horse_less carriage races were acceptable... This is why we have oval track, dirt oval track racing to this day in America.
In both cases. early horse_less carriages were not very reliable and required technical skills and expertise to keep the vehicle running. This is why early cars intended for motor sport evolved to having only two seats. One for the driver, one for the mechanic.. This became the origins and why "Sports Cars" to this day generally have two seats.
In time, the automobile developed enough reliability to exclude the mechanic. Removing the mechanic and related accommodations, made these cars lower weight which improved performance overall.
Thus was born the "Monoposto" (yes, it's Italian in the way Italians do stuff) or single seater racing automobile.. to this day.
Have a look at this Alfa Romeo 6C, Momoposto...
http://www.museostradale.com/radnor/alfaromeo6cvolpimonoposto_1938.htm
Any car involved in Motor_Sports can be considered a "Sports Car" or a car used for Motor Sports.
Bernice