bloomyoudaoicibaDictYouDict[bloom 词源字典]
bloom: [13] The Old English word for ‘flower’ was the probably related blossom, and English did not acquire bloom until the 13th century, when it borrowed it from Old Norse blómi. This came from Germanic *blōmon, a derivative of the Indo-European *bhlō- which also produced Latin flōs (whence English flower), the now archaic English verb blow ‘come into flower’, and English blade.
=> blade, blossom, blow, flower[bloom etymology, bloom origin, 英语词源]
bloom (n.1)youdaoicibaDictYouDict
"blossom of a plant," c. 1200, a northern word, from a Scandinavian source akin to Old Norse blomi "flower, blossom," also collectively "flowers and foliage on trees;" from Proto-Germanic *blomon (cognates: Old Saxon blomo, Middle Dutch bloeme, Dutch bloem, Old High German bluomo, German Blume, Gothic bloma), from PIE *bhle- (cognates: Old Irish blath "blossom, flower," Latin flos "flower," florere "to blossom, flourish"), extended form of root *bhel- (3) "to thrive, bloom" (see folio). Related to Old English blowan "to flower" (see blow (v.2)).

Transferred sense, of persons, is from c. 1300; meaning "state of greatest loveliness" is from early 14c.; that of "blush on the cheeks" is from 1752. Old English had cognate bloma, but only in the figurative sense of "state of greatest beauty;" the main word in Old English for "flower" was blostm (see blossom).
bloom (n.2)youdaoicibaDictYouDict
"rough mass of wrought iron," from Old English bloma "lump of metal; mass," which is of unknown origin. Identical in form to bloom (n.1), and sometimes regarded as a secondary sense of it, but evidence of a connection is wanting.
bloom (v.)youdaoicibaDictYouDict
mid-13c., blomen, from the noun (see bloom (n.1)). Related: Bloomed; blooming.