Merriam-Webster Collegiate Dictionary - master

 I. noun  Etymology: Middle English, from Old English magister & Anglo-French meistre, both from Latin magister; akin to Latin magnus large — more at much  Date: before 12th century  1.  a.  (1) a male teacher  (2) a person holding an academic degree higher than a bachelor's but lower than a doctor's  b. often capitalized a revered religious leader  c. a worker or artisan qualified to teach apprentices  d.  (1) an artist, performer, or player of consummate skill  (2) a great figure of the past (as in science or art) whose work serves as a model or ideal  2.  a. one having authority over another ; ruler, governor  b. one that conquers or ~s ; victor, superior in the new challenger the champion found his ~  c. a person licensed to command a merchant ship  d.  (1) one having control  (2) an owner especially of a slave or animal  e. the employer especially of a servant  f.  (1) dialect husband  (2) the male head of a household  3.  a.  (1) archaic Mr.  (2) a youth or boy too young to be called mister — used as a title  b. the eldest son of a Scottish viscount or baron  4.  a. a presiding officer in an institution or society (as a college)  b. any of several officers of court appointed to assist (as by hearing and reporting) a judge  5.  a. a ~ mechanism or device  b. an original from which copies can be made; especially a ~ recording (as a magnetic tape)  • ~ship noun  II. adjective  Date: 12th century being or relating to a ~: as  a. having chief authority ; dominant  b. skilled, proficient a prosperous ~ builder — Current Biography  c. principal, predominant  d. superlative — often used in combination a ~-liar  e. being a device or mechanism that controls the operation of another mechanism or that establishes a standard (as a dimension or weight)  f. being or relating to a ~ from which duplicates are made  III. transitive verb  (~ed; ~ing)  Date: 13th century  1. to become ~ of ; overcome ~ed his fears  2.  a. to become skilled or proficient in the use of ~ a foreign language  b. to gain a thorough understanding of had ~ed every aspect of publishing — Current Biography  3. to produce a ~ recording of (as a musical rendition)