/ Dictionary / Index G GI series: Meaning and Definition of Find definitions for: GI series Pronunciation: [key] gastrointestinal series: x-ray examination of the upper or lower gastrointestinal tract after barium sulfate is given rectallyor orally as a contrast medium. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Giselle Gish Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language