prepayment          
noun [ C or U ] (also pre-payment) uk/ˌpriːˈpeɪ.mənt/ us/ˌpriːˈpeɪ.mənt/
 预付;预付款
an arrangement in which a service or product is paid for, or partly paid for, before it is used or obtained, or the amount that is paid
  They moved into a home with a prepayment meter for electricity.
 A pre-payment of £50 as part of the rental cost is required. 需要预付50英镑作为租金的一部分。 
  finance & economics specialized提前偿还 
the act of paying a debt before it is due to be paid, or the amount that is paid 
  There is no penalty or fee for prepayment of a loan.
 Most contracts allow pre-payments of 10 to 20 percent of the balance each year without penalty. 大多数合同允许每年提前偿还余额的10%到20%而不会被罚款。 
 Synonym: prepay
 - More examples
 - Some petrol stations require prepayment.
 - People who have difficulty in paying for their water may prefer to have prepayment meters fitted.
 - Prepayments can erode returns if the investor is unable to quickly lend the money again at a similar rate.
 - Lenders charge prepayment penalties if you sell your home or refinance the mortgage before a specified time.