The actual product names of individual Canon lenses are fairly easy to decipher; they’ll include either the EF or EF-S designation, the focal length or focal length range of the lens, its maximum aperture, and some other information. Additional data may be engraved or painted on the barrel or ring surrounding the front element of the lens.
Here’s a decoding of what the individual designations mean:
EF-M. These lenses are designed specifically for the EOS M, and cannot be used on other Canon EOS cameras.
EF/EF-S. If the lens is marked EF, it can safely be used on any Canon EOS camera, film or digital, including ...