
1) Ancient Greek architecture
Found on
https://www.crosswordclues.com/clue/diaulos
[architecture] Diaulos, in ancient Greek architecture, was a peristyle round the great court of the palaestra, described by Vitruvius, which measured two stadia (1,200 ft.) in length, on the south side this peristyle had two rows of columns, so that in stormy weather the rain might not be driven into the inner part. ==Sources== ...
Found on
http://en.wikipedia.org/wiki/Diaulos_(architecture)

peristyle round the great court of the palaestra, described by Vitruvius, which measured two stadia (1,200 ft.) in length, on the south side this peristyle had two rows of columns, so that in stormy weather the rain might not be driven into the inner part. The word was also used in ancient Greece for a foot race of twice the usual length.[15]
Found on
http://en.wikipedia.org/wiki/Glossary_of_architecture

ancient Greek double flute
Found on
http://phrontistery.info/d.html

(from the article `Olympic Games`) ...also came to refer to the track on which the race was held and is the origin of the modern English word stadium. In 724 a two-length race, the ...
Found on
http://www.britannica.com/eb/a-z/d/44

ancient Greek athletics, a running race of 400 meters or two stades.
Found on
https://www.encyclo.co.uk/local/10135
No exact match found.