master

/ˈmastə/

noun

Someone who has control over something or someone.
The owner of an animal or slave.
The captain of a merchant ship; a master mariner.
The head of a household.
Someone who employs others.
An expert at something.
Mark Twain was a master of fiction.
A tradesman who is qualified to teach apprentices.
A schoolmaster.
A skilled artist.
A man or a boy; mister. See Master.
A master's degree; a type of postgraduate degree, usually undertaken after a bachelor degree.
She has a master in psychology.
A person holding such a degree.
He is a master of marine biology.
The original of a document or of a recording.
The band couldn't find the master, so they re-recorded their tracks.
The primary wide shot of a scene, into which the closeups will be edited later.
A parajudicial officer (such as a referee, an auditor, an examiner, or an assessor) specially appointed to help a court with its proceedings.
The case was tried by a master, who concluded that the plaintiffs were the equitable owners of the property. [...]
A device that is controlling other devices or is an authoritative source.
a master database
A person holding an office of authority, especially the presiding officer.
(by extension) A person holding a similar office in other civic societies.

To be a master.
To become the master of; to subject to one's will, control, or authority; to conquer; to overpower; to subdue.
To learn to a high degree of proficiency.
It took her years to master the art of needlecraft.
To own; to possess.
(especially of a musical performance) To make a master copy of.
(usually with in) To earn a Master's degree.
He mastered in English at the state college.