(From Greek πέτρα , “stone”, and γλύφειν, “to carve”).  An image created by removing part of a rock surface by pecking, abrading, incising or carving. When the the surface of the rock is removed, the lighter rock underneath is exposed, creating the petroglyph. Petroglyphs are found worldwide, and are often associated with prehistoric peoples.

A petroglyph of bighorn sheep near Moab, Utah. Photo: Jim Bouldin.