Who does Amir and Ulul Amr refer to
Q: I would like to know who does amir and ulul amr refer to in Quran and Ahaadith? Does it refer to amirul mumineen? If yes, then in our time upon whom will the title amir fit? Or can it refer to the principal of a madrasah, the teacher of a class, the sheikh of a khanqah, the leader of a tabligh jamaat, the leader of a jihad campaign etc.?