voucher
/ˈvautʃə(r); `vaʊtʃɚ/ n
1 (Brit) document, showing that money has been paid or promised, which can be exchanged for certain goods or services （代替现金的）凭单, 凭证, 代金券
`gift vouchers, ie offered as presents and later exchanged at the store for goods 礼券
special discount vouchers 优惠券
luncheon vouchers, ie tokens supplied by some employers, exchangeable for food at restaurants which have agreed to accept them 午餐代用券.
2 document showing that money has been paid for goods, etc received; receipt 收据; 收条.