bolsteryoudaoicibaDictYouDict[bolster 词源字典]
bolster: [OE] The idea underlying bolster ‘long pillow’ is of something stuffed, so that it swells up. It comes from a prehistoric Germanic *bolstraz, which was a derivative of *bolg-, *bulg- (source also of bellows, belly, billow and possibly bell, bellow, and bold). German has the related polster ‘cushion, pillow’.
=> bell, bellow, belly, billow, bold[bolster etymology, bolster origin, 英语词源]
bolster (v.)youdaoicibaDictYouDict
mid-15c. (implied in bolstered), "propped up, made to bulge" (originally of a woman's breasts), from bolster (n.). Figurative sense is from c. 1500, on the notion of "to support with a bolster, prop up." Related: Bolstering.
bolster (n.)youdaoicibaDictYouDict
Old English bolster "bolster, cushion, something stuffed so that it swells up," especially "long, stuffed pillow," from Proto-Germanic *bolkhstraz (cognates: Old Norse bolstr, Danish, Swedish, Dutch bolster, German polster), from PIE *bhelgh- "to swell" (see belly (n.)).