heavenyoudaoicibaDictYouDict[heaven 词源字典]
heaven: [OE] The precise origins of the word heaven have never been satisfactorily explained. Could it perhaps be related in some way to Greek kamára ‘vault, covering’, and thus originally have denoted ‘sky thought of as arching over or covering the earth’ (‘sky’ is at least as ancient a meaning of heaven as ‘abode of god(s)’, although it now has an archaic air)? Are the tantalizingly similar German, Swedish, and Danish himmel and Dutch hemel related to it (going back perhaps to a common Germanic source *hibn- in which the /b/ sound, which became /v/ in English, was lost – as in e’en for even – and a suffix *-ila- was adopted rather than the *-ina- that produced English heaven), or are they completely different words? The etymological jury is still out.
[heaven etymology, heaven origin, 英语词源]
heaven (n.)youdaoicibaDictYouDict
Old English heofon "home of God," earlier "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"), perhaps 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"].

Plural use in sense of "sky" is probably from Ptolemaic theory of space 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.