/ Thesaurus / M Synonyms of mass action Find synonyms for: Noun1. mass-action principle, mass action, principle, ruleusage: (neurology) the principle that the cortex of the brain operates as a coordinated system with large masses of neural tissue involved in all complex functioningWordNet 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