/ Dictionary / Index P petro: Meaning and Definition of Find definitions for: pet•ro Pronunciation: (pe'trō), [key] —n. the federally owned petroleum industry. petro- Pronunciation: [key] a combining form meaning “rock,” “stone,” used in the formation of compound words: petrology. petro- Pronunciation: [key] a combining form meaning “petroleum,” “the extraction and export of petroleum,” used in the formation of compound words: petrochemistry; petropower. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Petrinism Petrobrusian Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language