At some point I came across a term for an adjective that has been formed out of a proper noun. It happens often in the music, art and literary world, i.e. "Sufjanian" or "Dylan-esque." Other common usages are "Seusical" (referring to Dr. Seuss), "Steinbeckian" and "Kerouacian." What is that type of word called? I am almost positive it has a name. It's incredible to me as these terms are created when someone contributes something so unique and original to the world that they've ushered in a new paradigm against which their successors and peers are evaluated. I can't for the life of me remember what this is called.