Unique. One in a generation.
It's an old adage really that I really believe, but the mark of a true talent is that you know a voice as soon as they open their mouth. A distinctiveness that overrides all else, Aretha Franklin had that by the boatload. Add in the sheer 'feel', natural musicality, raw emotion, call it what you will, and those qualities she possessed in huge quantities as well.
Rest in peace Miss Franklin, your music will last forever.