hypethral

American  

[hi-pee-thruhl, hahy-] / hɪˈpi θrəl, haɪ- /

Or hypaethral

adjective

1. (of a classical building) wholly or partly open to the sky.

---

hypethral British  

/ hɪˈpiːθrəl, haɪ- /

adjective

1. the usual US spelling of hypaethral

---

Etymology

Origin of hypethral

First recorded in 1880–90; from Latin hypaethr(us) or directly from Greek hýpaithros “open to the sky,” equivalent to hyp- hyp- + aîthros “clear sky”; see ether) + -al ¹