a payment that you make to increase the amount of money, etc. to the level that is needed 附加付款 a phone top-up (= to buy more time for calls) 电话充值费 Students will have to pay top-up fees (= fees that are above the basic level). 学生必须交附加费用。
- (informal)
an amount of a drink that you add to a cup or glass in order to fill it again （重新斟满杯子的）补充饮料