Don't feel bad about not understanding the difference between Arc Fault Interrupters Circuit (AFCI) and Ground Fault Interrupters (GFCI). I've asked a few electricians to explain the difference with lackluster results - at least not so the average home owner would understand. I hope the following quote from SCC Electrical is helpful:
AFCIs vs. GFCIsAFCIs serve their purpose and must not be confused with a ground fault circuit interrupter or GFCI. GFCI devices are designed to provide protection from electric shock. Both AFCIs and GFCIs are important safety devices but they have different functions. AFCIs are designed to identify fire hazards; GFCIs detect and prevent shock hazards. Combination devices housing AFCI and GFCI protection in one unit are expected to be commercially available in the near future.