It's an English language question. As far as I gather, in the Middle ages "design"used to mean something like "craftmanship", while "art" was high arts. Both terms have evolved since then and I am not quite sure how. Not quite offtopic on a type-related forum, because some of us in the East use a multitude of anglophone tutorials to study art and graphic design yet I feel we do not exactly grasp the meaning of the words. E.g. I have never heard an arts professor talk about the "elements and principles of visual design", 10 elements, 5 principles etc. There is no such thing here that I know of. We use books by Bammes.
I am asking because I currently viewed a tutorial about drawing hair and therein was talk about "the design of the hair" - while it's clearly an art lecture (not coiffure, tho').