Crossword clue: a combining form from gr. rock, stone; as, petrology, petroglyphic.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
petro
5 letters
web-def
A combining form from Gr. rock, stone; as, petrology, petroglyphic.