stadium
Pronunciation: /ˈsteɪdɪəm/
noun ( plural stadiums or stadia /ˈsteɪdɪə/)

Origin:
late Middle English (in stadium (sense 2)): via Latin from Greek stadion. Sense 1 dates from the mid 19th century

Spelling help
The plural of stadium can be spelled either stadiums or stadia (like the original Latin).