/ Dictionary / Index P pure imaginary number: Meaning and Definition of Find definitions for: pure' imag'inary num'ber Pronunciation: [key] — Math. Math. a complex number of the form iy where y is a real number and i = &minus1sqrootover;. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. purehearted Pure Land Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language