/ Thesaurus / S Synonyms of saint lawrence seaway Find synonyms for: Noun1. Saint Lawrence Seaway, St. Lawrence Seawayusage: a seaway involving the Saint Lawrence River and the Great Lakes that was developed jointly by Canada and the United States; oceangoing ships can travel as far west as Lake SuperiorWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language