What is the meaning of the term 'Quid pro quo'?

on the value one thing for another the reason the thing speaks for itself

one thing for another

Quid pro quo: In Latin, quid pro quo literally means “something for something” or “one thing for another.” This is a Latin-derived expression referring to something done for someone in exchange for something of equal value in return. The concept of quid pro quo emerges in criminal sentencing where criminals receive reduced criminal sentences in exchange for providing testimony against others. Quid pro quo occurs in the contracts area where an individual gives up something, such as money, in exchange for something else, such as a service.