/ Thesaurus / G Synonyms of gi series Find synonyms for: Noun1. GI series, diagnostic test, diagnostic assayusage: diagnostic tests of the alimentary canal; usually involves inserting a contrast medium (such as barium sulfate) and taking an X-rayWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: eccentric Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language