stadion

noun2

1. •
   (historical) A Greek unit of distance based on standardized footraces, equivalent to about 185.4 metres.

   • The stadion did not suffice for the races of horses and chariots which had been favorites with the Greeks since the Trojan war. — 1883
2. •
   Synonym of stadium (“Ancient Greek racecourse”).

   • Nor can we think of these buildings as minor architectural incidents when we learn that the stadion at Athens seated between forty and fifty thousand people. — 1927