/ Thesaurus / A Synonyms of atomic number 20 Find synonyms for: Noun1. calcium, Ca, atomic number 20, metallic element, metalusage: a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animalsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language