borrowyoudaoicibaDictYouDict[borrow 词源字典]
borrow: [OE] Modern English borrow is a descendant of Old English borgian, which came from the Germanic base *borg-. This was a variant of *berg- (source of English barrow ‘mound’) and *burg- (source of English borough and bury). The underlying sense of the Germanic base was ‘protection, shelter’, and the development of meaning in the case of borrow seems to have been like this: originally, to borrow something from somebody was to receive it temporarily from them in return for some sort of security, which would be forfeited if the thing borrowed were not kept safe and eventually returned.

Gradually, the notion of giving some sort of concrete security, such as money, weakened into a spoken pledge, which by modern times had become simply the unspoken assumption that anything that has been borrowed must by definition be returned.
=> barrow, borough, bury[borrow etymology, borrow origin, 英语词源]
borrow (v.)youdaoicibaDictYouDict
Old English borgian "to lend, be surety for," from Proto-Germanic *borg "pledge" (cognates: Old English borg "pledge, security, bail, debt," Old Norse borga "to become bail for, guarantee," Middle Dutch borghen "to protect, guarantee," Old High German boragen "to beware of," German borgen "to borrow; to lend"), from PIE root *bhergh- (1) "to hide, protect" (see bury). Sense shifted in Old English to "borrow," apparently on the notion of collateral deposited as security for something borrowed. Related: Borrowed; borrowing.