/ Dictionary / Index P petrog.: Meaning and Definition of Find definitions for: petrog. Pronunciation: [key] petrography. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. petrodollars petrogenesis Related Content Daily Word Quiz: mamba Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language