/ Thesaurus / B Synonyms of biquadratic equation Find synonyms for: Noun1. biquadratic equation, biquadratic, equationusage: an equation of the fourth degreeWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language