master
//ˈmæstər//
Noun
A person who has control or authority over others, especially servants or workers
The servants obeyed their master without question.
A person who has achieved the highest level of skill or knowledge in a particular field or activity
She is a master of classical piano.
A male teacher or instructor
The master taught his students the art of calligraphy.
An original recording or document from which copies are made
The master recording was stored in a secure vault.
A person who holds a master's degree from a university
She is a master in computer science from Stanford University.
Verb
To acquire complete knowledge or skill in something through study or practice
It took her three years to master Japanese.
To gain control over or overcome something difficult
She worked hard to master her fear of public speaking.
Adjective
Being the main or principal version of something
Keep the master copy in a safe place.
Having or showing very great skill or proficiency
She is a master chef who can create amazing dishes.