I do not differentiate between graphic art and graphic design. Just "art" is too vague. That could include painting, photography, computer-generated art, architecture, oragami, drawing, illustrating, sculpting, engraving, conceptual art, etc, etc, and so on. It's like saying "design" by itself. What design? Graphic design, industrial design, or interior/landscape design?

"Art", as in graphic art, is the visualized media that one puts out. It lacks practical use, unlike the industrial design of how you'd make a new iron look or the nifty way you place bushes to stop prying eyes and frame your driveway. Graphic design is used to appeal to the heart. One can call a blob of color art, much like they can a brick hanging on a metal rod. Because, really, they are.