There simply is no better term. Sure the "Rock" part is easy enough and the only thing that really applies which leaves "Art" but was it created for arts sake as they say? Doubtful that it was considering what science might tell us of, from archaic to just prehistoric times, those standards of living in such a harsh environment that have been gleaned from the remains of the past. "Rock Graphics" has been suggested instead, but admitted to be another place holder for that unknown better term for certainly if the purpose was higher the term graphics falls short. "Indian Writing" frequents older reports and stories. This at least eludes to some form of communication or relation of meaning for more certainly some sort of higher purpose might have allowed for it's creation, perhaps by those important enough in society to be provided for while doing so, considering eras when day to day survival would have been so consuming of ones time and energies. But without anyone left from the creating culture to verify what if anything is being communicated we are left only with the extremely limited scientific facts and an unlimited supply of inference and compound inference. So accepting the most common lack of a better word, here is some of the finest rock art I've been privileged to visit and photograph. They call this one perfect.