A stadium (plural stadiums or stadia)〔''Stadia'' is the Latin plural form, but both are used in English. (Dictionary.com )〕 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.〔Nussli Group ("Stadium Construction Projects" )〕
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.〔''A Brief History of the Olympic Games'' by David C. Young, p. 20〕
"Stadium" is the Latin form of the Greek word "stadion" (''στάδιον''), a measure of length equalling the length of 600 human feet.〔(Στάδιον ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus〕 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 = , 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 - 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 sticklers sometimes apply ''stadia'' only to measures of length in excess of 1 stadium.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』