Vai arī vismaz iegādājies labu elektronisko angļu valodas skaidrojošo vārdnīcu ;)

No RHW:
quid pro quo (kwid' prō kwō), pl. quid pro quos, quids pro quo for 2.
1. (italics) Latin. one thing in return for another.
2. something that is given or taken in return for something else; substitute.
[1555–65; L quid prō quō lit., something for something; see WHAT, PRO1]