What is Balkan?

By definition I learned at school, Balkan consists of all land south of rivers Sava and Danube. With this I don't agree. I think Balkan consists of all people (and their countries) who have been conected in many ways during time. Therefore, Balkan for me is made of (alphabetically): Albania, Bosnia and Hercegovina, Bulgaria, Croatia, Greece, Hungary, Macedonia, Montenegro, Romania, Serbia, Slovenia and Turkey; and people living or coming from there.