noun pl. stadia -·dia (-dē ə), stadiums -·di·ums

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

Etymology: ME < L < Gr stadion, fixed standard of length, altered (infl. by stadios, standing) < earlier spadion < span, to draw, pull: see span