@rnv I seem to recall master having an etymology that went through old French and then back to classical Latin magister which means master in the sense of “teacher”. However after over 2,000 years, it’s going to shift, twist, and even break in its meanings over time. I’d be willing to bet there are easily 5-10 different definitions and shades of meaning on the word now (some even archaic), but some of which are  now problematic in how they relate to power dynamics in society. 
Of course if you want to really go crazy on historical linguistics, I recently ran across an etymology for the word Lord which was totally not what I was expecting but which is historically fascinating.