PIE *bhergh(1)の「守る」から。語源は harbour と同じ。何かを借りる際に担保が必要という古い考えから。
英語の語源
borrow
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 (v.)
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.
例文
1. Most people here cannot borrow from banks because they lack collateral.
品物を担保に出せないため、ここではほとんどの人が銀行から融資できない。
2.Investors can borrow an amount equal to the property 's purchase price.
投資家は不動産購入価格と同等の借入金を得ることができる。
3. "Why don't you borrow your sister's car?「said Cassandra stiffly.