"Classic" and "classical" are sometimes confused. "Classic" generally means "standard," "excellent," or "authoritative," as in the sentence "This is a classic example of putting the cart before the horse" or the phrase "classic car."
"Classical" has several definitions, most of which refer to Greek and Roman art, literature, and culture or to music of a certain style or era. One definition, however, is similar to that of "classic": "designating or of a specified area or course of study that is or has been standard or traditionally authoritative; not new, recent, and experimental." Example: "classical political theory" or "classical management science." There is a fine line between using "classic" and "classical" in these last examples, but most of the time the distinction is clear.