noun

1. a man who rules others or has control, authority, or power over something; specif.,
   1. a man who is head of a household or institution
   2. an employer
   3. one who owns a slave or an animal
   4. the captain of a merchant ship
   5. the one that excels in a contest, skill, etc.; victor or superior
   6. Chiefly Brit. a male schoolteacher or tutor
   7. a person whose teachings in religion, philosophy, etc. one follows or professes to follow
   8. Jesus Christ: with our, the, etc.
2. something regarded as having control, power, etc.
3. a person very skilled and able in some work, profession, science, etc.; expert; specif.,
   1. a highly skilled workman or craftsman qualified to follow his or her trade independently and, usually, to supervise the work of others
   2. an artist regarded as great
   3. Games, Sports a person recognized as having achieved the highest degree of skill chess master, golf master
4. a title variously applied to
   1. Archaic any man or youth: now superseded by the variant Mister, usually written Mr. when placed before the name
   2. a boy regarded as too young to be addressed as Mr.
   3. a man who heads some institution, group, activity, or place
   4. in Scotland, the heir apparent of a viscount or baron
5. 1. a metal matrix or mold made from the original recording and used to produce phonograph records in quantity
   2. a completed tape recording used to produce discs, cassettes, etc. for sale
6. Law any of several court officers appointed to assist the judge by hearing evidence, reporting on certain matters, etc.

Etymology: ME maistre < OE mægester, magister & OFr maistre, both < L magister, a master, chief, leader, orig., double compar. < base of L magnus, great < IE *me(h)- > much

adjective

1. being a master
2. of a master
3. chief; main; controlling; specif., designating a mechanism or contrivance that controls others or sets a standard or norm a master switch, a master test sheet

transitive verb

1. to become master of; control, conquer, etc.
2. Now Rare to rule or govern as master
3. to become an expert in (an art, science, etc.)
4. to make a master (sense ) of