Remit means:
* To send money or payment.
* To forgive or pardon (a debt, penalty, etc.).
* To refer (a matter) to another person or authority for decision.
Remittor is a noun that refers to:
* A person who sends money or payment.
* A person who refers a matter to another authority.
Therefore, "remit" is the root word that forms the basis of "remittor."