International Airport?

What constitutes an international airport?  When looking for flights to China, we had few choices, since we are leaving out of Raleigh Durham Airport.  It's supposed to be International Airport.  I don't know if they fly internationally.  We will be going from there to Dallas, TX.  I think in the past, we flew to Detroit, MI.  Can they claim international status if a carrier flies internationally from another airport?  I just don't get it.  If you bring up the list of carriers, there are not that many and even fewer that fly out of the country.