Thanks for this. I think it's safe enough to retain the term for now, but I'm willing to change my mind.
I have a subscription to the Oxford English Dictionary. It lists 3 principal meanings:
1.
Noun: A person or thing having control or authority.
I.d: A component of a system which controls or regulates the operation of one or more of the system's other components.
II. A teacher; a person qualified to teach.
III. As a title of rank or compliment.
And many more. Within each division there are many sub-meanings.
2. Noun: A vessel having masts, esp. one with a specified number of masts, as in five-master, seven-master, etc.
3. Verb:
To get the better of, to rule, and related senses.
Clearly, 1. applies. Within meaning one, there are many variants, many with connotations related to human relationships.
Furthermore, the OED contains dozens of related terms, such as master key and mastermind.
Edward