Of or relating to a monarch. Of the rank of a monarch. Of, relating to, or in the service of a kingdom. Issued or performed by a monarch: a royal warrant; a royal visit. Founded, chartered, or authorized by a monarch: a royal society of musicians. Befitting royalty; stately: royal treatment. Superior, as in size or quality. Used as an intensive: "It would be a first-class royal mess\u201d ( Sam Nunn). Informal A member of a monarch's family: "Among the resort's distinguished visitors are Swedish and Spanish royals\u201d ( Alistair Scott). Nautical A sail set on the royalmast. A paper size, 20 by 25 inches for printing, 19 by 24 inches for writing. the royal road A way or method that presents no difficulties: the royal road to success.