What's a scrum master? A servant leader, as you know. But why leader? Maybe it's just me but the term "leader" sounds like someone which is on an higher position, not exactly a boss but not so far.
For that reason I'm not really comfortable with that definition, I prefer something that reflects better the helping and coaching actions.
Master of ceremonies is another definition, I like it even if I'm not in the religion thing. It render the idea of someone that help the team having the right pace following a series of repetitive rites, people can trust him and ask his wise words in case of doubt. I like it even if I think is a bit too passive and doesn't represent me too much.
A scrum master is mr. Wolf, he's here to solve impediments. That's true of course but it's not, at least not at all. I like solve impediments believe me, but I think one of the mission of the SM is to make the team able to help itself, with self organization. I would like to be so great in my job that the team tell me they don't need me anymore.
A scrum master is an orchestra director, someone who transform a bunch of talented people into a motivated team who perform the symphony.
A scrum master is a trainer that drive the team to win the championship.
When I think the scrum master role, I figure a sort of wise karate master, someone who could easily beat the bully but instead teach the weak how to defend himself. And not just physical training but also mentally.
I think the scrum master is all of the above and more
Just my 2 cents