There is no "slave" in Git, but the term "master", like many things in Git, is taken from BitKeeper, which did have a "slave". Or so I've read, for example here: https://english.stackexchange.com/questions/474419/does-the-...

There isn't, but if you are going to learn about computers then you're going to hear a lot about master/slave relationships. If you don't get exposed to that kind of jargon then it wouldn't surprise me if you don't have that connotation as strongly and instead only thought of master as in "mastery" or the degree after a bachelors.