/ Dictionary / Index P phototrophic bacteria: Meaning and Definition of Find definitions for: phototroph'ic bacte'ria Pronunciation: [key] — Bacteriol. Bacteriol. a group of bacteria, including the green bacteria and purple bacteria, whose energy for growth is derived from sunlight and whose carbon is derived from carbon dioxide or organic carbon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. phototroph phototropic Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language