When you remortgage, you borrow money against a house you already own. You may take a second loan on top of the first one, or you may make the old loan bigger so the bank hands you more cash. People do this for a large cost that ordinary wages will not cover — a repair, a child’s studies, another flat. Though actually, in Britain the word is used more loosely than that tidy picture. A lot of families say they remortgage when they simply switch the house loan to a new bank, often to get a better rate, even if they do not borrow extra. Banks and newspapers like that meaning; it is everyday money talk there. Careful writing sometimes calls the switch refinance, and the extra loan a second mortgage. The picture underneath is the same: the house is the bank’s safety, and you are changing the loan on it. It is a money-and-law word. You will hear it from banks, brokers, and the property pages, not much at the dinner table unless someone is talking about their house. American English prefers refinance for switching banks, and second mortgage for the extra loan.

增貸、辦二胎；英國口語也常指轉貸（換銀行重辦房貸）