Tennis polo
The sport is played on a grass field between 80 and 100 yards long and 50 to 65 yards wide. The goal area is a semicircular line with an 11-yard radius and the penalty mark at 13 yards from the goal. An experimental rule has a second semicircular line on the field with a 17-yard radius. Generally, a field for gridiron football or soccer can be used.
Stadion (unit)
The stadion (; ), formerly also anglicized as stade, was an ancient Greek unit of length, based on the length of a typical sports stadium of the time. According to Herodotus, one stadion was equal to 600 Greek feet ("podes"). However, the length of the foot varied in different parts of the Greek world, and the length of the stadion has been the subject of argument and hypothesis for hundreds of years. Various hypothetical equivalent lengths have been proposed, and some have been named. Among them are: