Graphic design is the creation of new solutions to problems within the medium of visual communication, either in 2D or 3D, on paper or digitally. The output is usually something that can be reproduced in order to deliver its objective many times.
Graphic design output includes logos, web site user interfaces, tattoos, sketches for fashion or industrial design, typefaces, print, animated characters, advertisements, flyers, movie credits, newspaper headlines, and designs for textiles. This is just a small part of what can be designed graphically. What they have in common is output that will be consumed through visual media.