/ Dictionary / Index C CI: Meaning and Definition of Find definitions for: CI Pronunciation: [key] counterintelligence. Ci Pronunciation: [key] curie; curies. C.I. Pronunciation: [key] Channel Islands. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ci (Thesaurus) chytrid CIA Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language