/ Thesaurus / A Synonyms of atomic number 44 Find synonyms for: Noun1. ruthenium, Ru, atomic number 44, metallic element, metalusage: a rare polyvalent metallic element of the platinum group; it is found associated with platinumWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: torrid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language