Breadcrumb Home > Thesaurus Cite Synonyms of rubidium Find synonyms for: Noun1. rubidium, Rb, atomic number 37, metallic element, metalusage: a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and polluciteWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.See also: rubidium (Dictionary) Related Content Daily Word Quiz: philistine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language Synonyms Index