CI
- Ci – (s) Curie
- CI
- (s) Chile (FIPS 10-4 country code)
- Côte d'Ivoire (ISO 3166 digram)
- (i) Counter-Intelligence
- 101 (in Roman numerals)
- CIA
- (i) Cairo International Airport
- Central Intelligence Agency
- Culinary Institute of America
- CIAO
- (i) Critical Infrastructure Assurance Office
- Component-Integrated ACE ORB
- CIB – (i) Complete In Box (Internet auction/trading listings)
- CIBC – (i) Canadian Imperial Bank of Commerce (obsolete)
- CICS – (a) Customer Information Control System (IBM mainframe software; "kicks" or "C-I-C-S")
- CID
- (p) Combat Identification
- (i) Criminal Investigation Division
- Criminal Investigations Department
- CID - Certified Interior Designer - A Certified Interior Designer (CID) licensed in New York (USA) plans, designs, supervises and/or consults on various aspects of interior spaces.
- CIÉ – (i) Commission internationale de l'éclairage
- CIEF – (i) Comité international d'enregistrement des fréquences (International Frequency Registration Board)
- CIF – (i) Cost, Insurance, and Freight (Paid) (shipping)
- CIMIC – (p) Civil-Military Co-operation
- CIMMYT – (a/i) Centro Internacional de Mejoramiento de Maíz Y Trigo (Spanish, "International Maize and Wheat Improvement Center")
- CINC – (p) Commander in Chief
- CINEOS – (a) Campo Imperatore Near-Earth Objects Survey
- CIO
- (i) Chief information officer
- Congress of Industrial Organizations
- CIP – (a) Combat Identification Panel
- CIPE – (i) (European) Centre for International Political Economy
- CIR – (i) (Commander's) Critical Information Requirements
- CIR – (s) Corotating Interaction Region
- CIS
- (i) Canadian Interuniversity Sport
- Commonwealth of Independent States
- Command and Information System
- Communication and Information System
- CISA – (a) (U.S.) C4I Integration Support Activity
- CISB – (i) Complete In Sealed Box (Internet auction/trading listings)
- CISPR – (i) Comité international spécial des perturbations radioélectriques (Special International Committee on Radio Interference)
- CISSP – (i) Certified Information Systems Security Professional
- CITES – (p) Convention on International Trade in Endangered Species (of Wild Fauna and Flora) ("sigh-tease")
- CITS – (i) Combat Identification Training System
- CIV – (s) Côte d'Ivoire (ISO 3166 trigram)
- CIVETS – (a) Colombia, Indonesia, Vietnam, Egypt, Turkey, South Africa (economics)
- CIVPOP – (p) Civilian Population
- CIWS – (i) Close-In Weapon System
- CHRS – Canadian Heart Rhythm Society
Read more about this topic: List Of Acronyms And Initialisms: C