Definitions:
a man who has people working for him, especially servants or slaves

a man in charge of an organization or group.

a skilled practitioner of a particular art or activity

a person who holds a second or further degree

used as a title prefixed to the name of a boy not old enough to be called ‘mr’

an original recording, film, or document from which copies can be made

having or showing very great skill or proficiency

main; principal

acquire complete knowledge or skill in (a subject, technique, or art)

gain control of; overcome

make a master copy of (a film or recording)

a ship or boat with a specified number of masts