A stadium (plural stadiums or stadia) is a place or venue for (mostly) outdoor sports, concerts, or other events and consists of a field or stage either partly or completely surrounded by a tiered structure designed to allow spectators to stand or sit and view the event.
Pausanias noted that for about half a century the only event at the ancient Greek Olympic festival was the race that comprised one length of the stade at Olympia, where the word "stadium" originated.
Most of the stadiums with a capacity of at least 10,000 are used for association football. Other popular stadium sports include gridiron football, baseball, ice hockey, basketball, cricket, rugby union, rugby league, Australian-rules football, Gaelic football, rugby sevens, field lacrosse, bandy, athletics, hurling, field hockey, Kabaddi, and bullfighting. A large number of large sports venues are also used for concerts. Basketball is the most popular arena (or indoor stadium) sport in the world. Large race circuits and large horse racing tracks are not stadiums, but sports venues, because the entire playing surface can't be seen from the stands. For the difference, compare List of stadiums by capacity with List of sports venues by capacity.
"Stadium" is the Latin form of the Greek word "stadion" (στάδιον), a measure of length equalling the length of 600 human feet. As feet are of variable length the exact length of a stadion depends on the exact length adopted for 1 foot at a given place and time. Although in modern terms 1 stadion = 600 ft (180 m), in a given historical context it may actually signify a length up to 15% larger or smaller.
The equivalent Roman measure, the stadium, had a similar length – about 185 m (607 ft) – but instead of being defined in feet was defined using the Roman standard passus to be a distance of 125 passūs (double-paces).
The English use of stadium comes from the tiered infrastructure surrounding a Roman track of such length.
Most dictionaries provide for both stadiums and stadia as valid English plurals, although etymological purists sometimes apply stadia only to measures of length in excess of 1 stadium.