Hypaethral

Hypaethral is an ancient temple with no roof. (From the Latin hypaethrus, from Ancient Greek ὕπαιθρος hupaithros ὑπό hupo- "under" and αἰθήρ aither "sky, air".) It has instead a hypaethros or hypaethral opening. It was described by the Roman architect Vitruvius in his treatise On Architecture written for the emperor Caesar Augustus probably about 15 BC. This term is in distinction from cleithral, which is covered with a roof.