[sta.di.um] n, pl -dia or -di.ums [ME, fr. L, fr. Gk stadion] (14c) 1 a: any of various ancient Greek units of length ranging in value from 607 to 738 feet (about 185 to 225 meters) b: an ancient Roman unit of length equal to 607 feet (185 meters)
2. a: a course for footraces in ancient Greece orig. one stadium in length b: a tiered structure with seats for spectators surrounding an ancient Greek running track c: a large usu. unroofed building with tiers of seats for spectators at sports events 3 [NL, fr. L]: a stage in a life history; esp: one between successive molts