EF means Electro Focus Lens, Well these EF lenses introduced around 1987. EF-S lenses made for EOS cameras with 1.6X Crop (camera have APS-C sized sensors) introduced around 2003. EF lenses can be mounted on EF-S bodies while EF-S lenses cannot be mounted on EF bodies.
EF-S bodies of Canon
EOS 300D/Digital Rebel
EOS 350D/Digital Rebel XT
EOS 400D/Digital Rebel XTi
EOS 450D/Rebel XSi
EOS 500D/Rebel T1i
EOS 550D/Rebel T2i
EOS 1000D/Rebel XS
EOS 7D
EOS 20D …… EOS 60D
