heaven (n.)

Old English heofon "home of God," earlier "the visible sky, firmament," probably from Proto-Germanic *hibin-, dissimilated from *himin- (cognates Low German heben, Old Norse himinn, Gothic himins, Old Frisian himul, Dutch hemel, German Himmel "heaven, sky"), which is of uncertain origin. Perhaps literally "a covering," from a PIE root *kem- "to cover" (also proposed as the source of chemise). Watkins derives it elaborately from PIE *ak- "sharp" via *akman- "stone, sharp stone," then "stony vault of heaven."

From late 14c. as "a heavenly place; a state of bliss." Plural use in sense of "sky" probably is from Ptolemaic theory of space as composed of many spheres, but it also formerly was used in the same sense as the singular in Biblical language, as a translation of Hebrew plural shamayim. Heaven-sent (adj.) attested from 1640s.