Breadcrumb Home > Thesaurus > M Synonyms of mullion Find synonyms for: Noun 1. mullion, strip, slip usage: a nonstructural vertical strip between the casements or panes of a window (or the panels of a screen) WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of mullion (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Hanukkah Origins of the Christmas Holiday Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 Krampus: The Christmas Devil Kwanzaa ✖ Related Content Daily Word Quiz: anomie Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language