tab noun [C] (BILL)
the tab = the total money charged in a restaurant or hotel for food, drinks, etc.（待付的）账单，账款。
常见短语pay the tab付帐单 / pick up the tab 承担全部费用 / throw up a tab 赊帐。

【例句】
He kindly offered to pick up the tab (= pay).
他客气地主动要求付账。

You can soon run up a big bill if you buy goods on credit.
如果你老是这样赊帐购物，那你的帐单金额会大大增加。