an Entity references as follows:
In classical architecture, hypaethral describes an ancient temple with no roof. (From the Latin hypaethrus, from Ancient Greek ὕπαιθρος hupaithros ὑπό hupo- "under" and αἰθήρ aither "sky, air".) It was described by the Roman architect Vitruvius in his treatise De architectura, written for the emperor Caesar Augustus probably about 15 BC.