It means peace be upon you and it's how you say hello here. Or you can say MarHaba, or you can say Ahlan wa sahlan, but the first one is my favorite. This morning I learned that Arabic is a semetic language and, at least to me, it sounds a bit like a cross between German and Spanish. Sentences don't use verbs either so if I ask you where you are from your reply would be "I from." I also learned that the word for student is Taalib(boy)/Taaliba(girl). So to say that I am a student I would say "I student" or " 'ana Taabliba."
'Ana taaliba fi Jeamat Carnegie Mellon fi Qatar."