/ Dictionary / Index P plate girder: Meaning and Definition of Find definitions for: plate' gird"er Pronunciation: [key] an iron or steel beam built up from plates and shapes welded or riveted together, usually including a plate or plates for a web, four angle irons forming two flanges, and a pair of plates to reinforce the flanges. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plateful plate glass Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language