a vessel having (so many) masts; -- used only in compounds; as, a two-master.-a male person having another living being so far subject to his will, that he can, in the main, control his or its actions; -- formerly used with much more extensive application than now. (a) the employer of a servant. (b) the owner of a slave. (c) the person to whom an apprentice is articled. (d) a sovereign, prince, or feudal noble; a chief, or one exercising similar authority. (e) the head of a household. (f) the male head of a school or college. (g) a male teacher. (h) the director of a number of persons performing a ceremony or sharing a feast. (i) the owner of a docile brute, -- especially a dog or horse. (j) the controller of a familiar spirit or other supernatural being.-one who uses, or controls at will, anything inanimate; as, to be master of one's time.-one who has attained great skill in the use or application of anything; as, a master of oratorical art.-a title given by courtesy, now commonly pronounced mister, except when given to boys; -- sometimes written mister, but usually abbreviated to mr.-a young gentleman; a lad, or small boy.-the commander of a merchant vessel; -- usually called captain. also, a commissioned officer in the navy ranking next above ensign and below lieutenant; formerly, an officer on a man-of-war who had immediate charge, under the commander, of sailing the vessel.-a person holding an office of authority among the freemasons, esp. the presiding officer; also, a person holding a similar office in other civic societies.-to become the master of; to subject to one's will, control, or authority; to conquer; to overpower; to subdue.-to gain the command of, so as to understand or apply; to become an adept in; as, to master a science.-to own; to posses.-to be skillful; to excel.