/ Dictionary / Index P petrogram: Meaning and Definition of Find definitions for: pet•ro•gram Pronunciation: (pe'tru-gram"), [key] — n. a drawing or painting on rock, esp. one made by a member of a prehistoric people. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Petrograd petrograph 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