/ Thesaurus / G Synonyms of gideon algernon mantell Find synonyms for: Noun1. Mantell, Gideon Algernon Mantellusage: English geologist remembered as the first person to recognize that dinosaurs were reptiles (1790-1852)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: dispel Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language