/ Thesaurus / J Synonyms of j particle Find synonyms for: Noun1. J particle, psi particle, meson, mesotronusage: a neutral meson with a large massWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: philanthropy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language