1 [count] : someone who has control or power over others: such as a : someone (especially a man) who has a servant or slave
▪ As a slave he was required to do his master's bidding without question.
b : someone (especially a man) who owns a pet (such as a dog)
▪ The dog was always obedient to its master.
c formal : the male head of a household
▪ the master and mistress of the house
d : a man who is in charge of the people on a ship
▪ a ship's master 2 [count] : a person who has control of something — usually + of ▪ He was the master of his feelings. [=he was able to control his own feelings] ▪ She proved herself (to be) master of the situation. ▪ We are the masters of our own destiny. 3 [count] : a person who has become very skilled at doing something
▪ She is a master of her craft. ▪ a chess master ▪ a Dutch master [=one of the great Dutch painters of the past] — often + at ▪ He is a master at manipulating people. — see also grand master, past master 4 a [count] old-fashioned : a male teacher — see also headmaster, schoolmaster
b Master — used as a title for the male head of certain British colleges ▪ He was Master of Balliol. 5 [count] : a person who has received a master's degree
▪ a master of arts 6 [count] : an original version of something (such as a recording) from which copies can be made 7 Master formal + old-fashioned — used as a title for a boy who is too young to be called Mister ▪ Master Timothy