Ancient Roman architect and engineer Vitruvius used the Latin word hypaethrus to describe temples in which the "cella" (the part of the temple housing an image of the deity) was wholly or partially uncovered. "Hypaethrus" is a word sculpted from the Greek prefix hypo-, meaning "under or beneath," and the Greek word aithēr, meaning "air or heaven." In the late-18th century, English classicists adopted the remodeled form "hypaethral" in their writings of ancient architecture. Another adjective that they occasionally employed is "cleithral," which designates temples having roofed central spaces. ("Cleithral" comes from "kleithra," the Greek word for "lattice.")
Word History
Etymology
Latin hypaethrus exposed to the open air, from Greek hypaithros, from hypo- + aithēr ether, air — more at ether