/ Thesaurus / M Synonyms of mason and dixon's line Find synonyms for: Noun1. Mason-Dixon line, Mason and Dixon line, Mason and Dixon's lineusage: the boundary between Maryland and Pennsylvania; symbolic dividing line between North and South before the American Civil WarWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language