master /ˈmɑːstər/ noun [C]
IN CHARGE › In the past, a servant's master was the man that they worked for.
TEACHER old-fashioned › a male teacher: the Latin master
SKILL › someone who does something very well: He was a master of disguise.
FOR COPYING › a document or recording from which copies can be made
Master of Arts/Science, etc › a higher university qualification which usually takes 1 or 2 more years of study after your first qualification, or a person who has this qualification
Master's (degree) › a higher university qualification: to study for a Master's degree
Master formal › a title for a boy, used before his family name or full name: Master Thomas Mills