What is the difference between communication design and graphic design?

Graphic design is everything that goes into design - clothes, signs, color choices to attract people, and so on - some of it is communication but usually limited - those big signs in a drugs store that say Pharmacy and Beverages are part of the graphic design as is the wall paint color and floor coverings that suggest durability or happiness. Visual communication should be primarily communication - ads, directions, getting crowds to move at events using visual and changing signs.