It means concession, grace, favor, privilege, breneficio, prevenda. Don, gift. It also means gift. In another meaning it means prize, reward, award, caprice.
It has various uses in Spanish, but all are associated in some way. It means "gift, prize, benefit, reward, will (to give something)". It comes from the Latin merces, edis ("reward"). 2º_ It was a courtesy title to address someone who might not have one of their own but deserved respect.
MERCED: Will or discretion of someone.