/ Dictionary / Index C complexing agent: Meaning and Definition of Find definitions for: com•plex'ing a"gent Pronunciation: (kum-plek'sing), [key] — Chem. Chem. See under(def. 10). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. complex fraction complex ion Related Content Daily Word Quiz: verdant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language