/ Thesaurus / I Synonyms of imaginary number Find synonyms for: Noun1. complex number, complex quantity, imaginary number, imaginary, numberusage: (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language