master

1 master /ˈmæstɚ/ Brit /ˈmɑːstə/ noun
plural masters
1 master
/ˈmæstɚ/ Brit /ˈmɑːstə/
noun
plural masters
Britannica Dictionary definition of MASTER
1 
[count] : someone who has control or power over others: such as
a  old-fashioned : someone (especially a man) who employs a servant
b  : someone (especially a man) who holds another person in slavery
◊ This meaning of master was used in the past and is strongly associated with the history of slavery in the U.S.
c  : someone who owns a pet (such as a dog)
d  formal : the male head of a household
e  : a person who is in charge of the people on a ship
2 
[count] : a person who has control of something — usually + of
3 
[count] : a person who has become very skilled at doing something
— often + at — 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
5 
[count] : a person who has received a master's degree
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

jack-of-all-trades, master of none

— see jack-of-all-trades

serve two masters

— see 1serve
2 master /ˈmæstɚ/ Brit /ˈmɑːstə/ adjective
2 master
/ˈmæstɚ/ Brit /ˈmɑːstə/
adjective
Britannica Dictionary definition of MASTER
always used before a noun
1 
: highly skilled
2 
: largest or most important
3 
— used to describe an original version from which other copies can be made
3 master /ˈmæstɚ/ Brit /ˈmɑːstə/ verb
masters; mastered; mastering
3 master
/ˈmæstɚ/ Brit /ˈmɑːstə/
verb
masters; mastered; mastering
Britannica Dictionary definition of MASTER
[+ object]
1 
: to succeed in controlling (something, such as an emotion)
2 
: to learn (something) completely : to get the knowledge and skill that allows you to do, use, or understand (something) very well