Main Entry: wel·kin

Pronunciation: \ˈwel-kən\

Function: noun

Etymology: Middle English, literally, cloud, from Old English wolcen; akin to Old High German wolkan cloud

Date: 12th century

1 a : the vault of the sky : firmament <the sun of heaven…made the western welkin blush — Shakespeare> b : the celestial abode of God or the gods : heaven
2 : the upper atmosphere