How is a veto used?
A veto is used when the President rejects a bill.
No- the word "veto' is not used to any action by Congress. Congress can repeal a law which means to cancel it or nullify it. The word "veto" is used for the president's action of objecting to a bill that has been passed and sending it back to Congress with his objections. "Veto" means "I forbid" in Latin.