Real Dictionary

down payment
countable noun: If you make a down payment on something, you pay only a percentage of the total cost when you buy it. You then finish paying for it later, usually by paying a certain amount every month.

down payment in American English
an initial, partial payment on a purchase
noun: an initial amount paid at the time of purchase, in installment buying, time sales, etc

down payment in British English
noun: the deposit paid on an item purchased on hire-purchase, a mortgage, etc