/ Dictionary / Index C circle of least confusion: Meaning and Definition of Find definitions for: cir'cle of least' confu'sion Pronunciation: [key] — Optics. Optics. the smallest cross section in a beam of paraxial rays, lying in the plane of least spherical aberration. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. circle of declination circle-out Related Content Daily Word Quiz: languid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language