Put simply, Canon EF-S lenses are designed solely for use on Canon APS-C DSLRs. Canon EF lenses are designed to work with full frame and APS-C DSLRs from Canon.
The full frame sensor is the larger of the two. It is the size of a 35mm film frame – 36mm x 24mm.
The Canon APS-C sensor is smaller at 22.3mm x 14.9mm. The field of view (how much of a scene you can see through the viewfinder) is smaller when using the same lens on an APS-C format camera than it would be on a full frame camera. Hope this is of some help. You can also google search the information on these two lens types.