What is " QUID PRO QUO"?
Refer to the title.
What is that? ( The chinese subtitles told me it meant " to be equal to")
Is it a quote from other language? Where does it come from?
I had found it a couple of times in the moive Hannibal, Comedy The Big Bang Theory 16th episode in the second serie......Sorry for a slip of a pen...
The chinese subtitles told :" something like it is your turn to exchange something"

Question

What is " QUID PRO QUO"?
Refer to the title.
What is that? ( The chinese subtitles told me it meant   " to be equal to")
Is it a quote from other language? Where does it come from?
I had found it a couple of times in the moive Hannibal, Comedy The Big Bang Theory 16th episode in the second serie......Sorry for a slip of a pen...
The chinese subtitles told :" something like it is your turn to exchange something"

Answer

It's from Latin. It means "this for that".

I found this line from Hannibal:
If I help you, Clarice, it will be "turns" for us too. I tell you things, you tell me things. Not about this case, though. About yourself. Quid pro quo. Yes or no?

See? He is telling her something and she is telling him something. That is what quid pro quo means. Hope that helps.

Answer

'to give something in exchange for something else' = 'you scratch my back and I'll scratch yours" / "Tit for tat"
Yuanshuo - "I'll give you the Qing province as a quid pro quo for helping me against Cao Cao"
Cao Cao: "Yeh, you scratch my back and I'll scratch yours"