Definition of petrograph in English:
petrograph
noun
A carving, especially writing, upon a rock; a rock inscription.
Pronunciation
petrograph
/ˈpɛtrə(ʊ)ɡrɑːf/ /ˈpɛtrə(ʊ)ɡraf/ Origin
Early 19th century; earliest use found in Robert Southey (1774–1843), poet and reviewer. From petro- + -graph.