noun pl. stadia , stadiums
- in ancient Greece and Rome,
- a unit of linear measure, equal to about 607 feet (185 meters)
- a straight track for footraces, typically one stadium in length, with tiers of seats for spectators on each side
- a large, oval, round, or -shaped, usually open structure, as for football, track events, etc., with tiers of seats for thousands of spectators
- Biol. a period or stage in the life history of an animal or plant