Strictly speaking, any term such as "areology" "selenology" also have the same problem as "planetary science", as they just mean "[astronomical body], the study of", which obviously incorporates everything about the body in question and not just the lithology of it.

However, "Planetary Science" as a term for this sort of study has the additional problem that it doesn't actually apply to the study of the lithology of fakey non-planets like Pluto or Ceres, nor moons like The Moon or Titan, as none of those are planets by any currently accepted scientific standard.