What is a Moor?

Throughout Acts I and II, I noticed that many of the characters refered to Othello as a "moor." What exactly is a moor, though? According to Marriam Webster, a moor is one the Arab or Berber conqueres of Spain. (http://www.merriam-webster.com/dictionary/Moor) I was slightly confused by this. Before looking up the definition, I never once thought that Moor was a word dealing with nationality. To be honest, I had absolutley no idea what it meant. But while working in my small group the other day during class the race of Othello did come up. We were confused if he was black, just tan, who knows! But now I know! Othello was a Berber, which is a person from Nothern Africa. While I'm not exactly sure how much importance this has to the story, at least I know what the word means now!