To take and use (something belonging to someone else) with the intention of returning it. She decided to borrow a book from the library for her research.
To adopt or take over (an idea, practice, or word) from another source. The English language has borrowed many words from Latin.
To take money from a person or financial institution with the agreement to pay it back later. He had to borrow money from the bank to buy a new car.
(Arithmetic) To take one unit from the next higher place value in order to perform a subtraction operation. When subtracting 47 from 123, you borrow 1 from the tens column.