/ Dictionary / Index C circulus: Meaning and Definition of Find definitions for: cir•cu•lus Pronunciation: (sûr'kyu-lus), [key] — pl. -li any of the concentric circles on each scale of a fish, each of which indicates the annual growth of that scale. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. circulatory system circum- Related Content Daily Word Quiz: dentifrice Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language