- rock or stone: petrographyalso, before a vowel, petr-
- petroleum: petrochemical
- of or relating to the petroleum business: petrodollars, petropolitics
Origin of petro-from Classical Greek petra, rock, or petros, stone
or petri- or petr-
- Rock; stone: petroglyph.
- Petroleum: petrochemistry.
Origin of petro-Greek from petros stone ; see per-2 in Indo-European roots.