master
n. countablen. someone who is very skilled at a job or activity. It can also mean a person who has power over others or a specific type of university degree.
n. a person who has acquired complete proficiency or skill in a specific craft or discipline. Also used to denote a person with legal or social authority over others, or a postgraduate academic degree.
She is a master of the violin after years of practice.
After completing his undergraduate studies, he decided to pursue a master in international relations to improve his career prospects.
The apprentice spent a decade observing the master at work, eventually internalising the subtle techniques that distinguished a functional piece of furniture from a true work of art.
When referring to an academic degree, it is often capitalised (Master's) and used with a possessive 's'.
I have a master degreeI have a master's degreeWhen describing the academic qualification, the possessive form 'master's' is required.