| Acronym | Definition |
|---|
| CI | Counterintelligence |
| CI | Continuous Improvement (business quality/productivity assurance) |
| CI | Caller ID |
| CI | Cubic Inch |
| CI | City (IRB) |
| CI | Customer Information |
| CI | Chile |
| CI | Cote d'Ivoire (country code, top level domain) |
| CI | Cayman Islands |
| CI | Confidence Interval |
| CI | Check In (IBM) |
| CI | Christmas Island |
| CI | Corporate Information |
| CI | Call-In |
| Ci | Curie |
| CI | Criminal Intent (Law & Order TV series) |
| CI | Cirrus (cloud formation) |
| CI | Community Involvement |
| CI | Conservation International |
| CI | Competitive Intelligence |
| CI | Consumers International (UK) |
| CI | Corporate Identity |
| CI | Common Interface |
| CI | Communications International |
| CI | Critical Information |
| CI | Canadian Idol (TV show) |
| CI | Consumers' International |
| CI | Continuous Integration |
| CI | Cast Iron |
| CI | Channel Islands (UK) |
| CI | Copyright Infringement |
| CI | Clinical Investigation |
| CI | Criminal Investigation |
| CI | Canary Islands |
| CI | CARE International (global humanitarian organization) |
| CI | Contraindicated |
| CI | Critical Illness |
| CI | Capital Investment |
| CI | Cognitive Impairment |
| CI | Cochlear Implant (audiological device that restores hearing to the deaf) |
| CI | Coney Island (Brooklyn, NY, USA) |
| CI | Critical Issues |
| CI | Critical Infrastructure |
| CI | Combustion Institute |
| CI | Cost Index |
| CI | Cumulative Incidence (epidemiology) |
| CI | Configuration Item |
| CI | Correctional Industries (Nebraska) |
| CI | Collective Intelligence |
| CI | Central Indiana |
| CI | Chlorine Institute |
| CI | Cotton Incorporated |
| CI | Certificate of Insurance |
| CI | Chris Isaak (musician) |
| CI | Correctional Institution |
| CI | Compression Ignition |
| CI | Cardiac Index |
| CI | Community Informatics |
| CI | Crisis Intervention |
| CI | Configuration Interaction |
| CI | Command Interpreter |
| CI | Computer Interface |
| CI | Construction Inspector |
| CI | Caritas Italiana (Italian charity) |
| CI | Confidential Informant |
| CI | Counterinsurgency |
| CI | Collegiate Institute |
| CI | Cook Inlet |
| CI | Corporate Investment |
| CI | Commercial Items (FAR Part 12) |
| CI | Corrosion Inhibitor |
| CI | Chemical Ionization |
| CI | Cost & Insurance |
| CI | Cooperazione Italiana (Italian Cooperation) |
| CI | Commercial Invoice |
| CI | Core Infrastructure |
| CI | Control Interface |
| CI | Cost Incurred |
| CI | Catcher's Interference (baseball) |
| CI | Colour Index |
| CI | Communist International (also COMINTERN or Third International) |
| CI | Clinical Instructor |
| CI | Criminal Investigator |
| CI | Code Inspection |
| CI | Characteristic Impedance |
| CI | Coeficiente Intelectual (Spanish: Intelligence quotient) |
| CI | Crime & Investigation (TV series) |
| CI | Condition Index |
| CI | Community of Interest |
| CI | Compassion International (relief charity) |
| CI | Consistency Index |
| CI | Central Islip (Long Island, New York) |
| CI | Cooper Institute |
| CI | Command Information |
| CI | Component Instrumentation |
| CI | Connection Identifier |
| CI | Control Interval |
| CI | Communications Interface |
| CI | Clock Input |
| CI | Channel Interface |
| CI | Complete Integration |
| CI | Complexity International (journal) |
| CI | Compliance Inspection |
| CI | Carnegie Institute |
| CI | Center Island |
| CI | Cell ID |
| CI | City Inspector |
| CI | Central Instance (SAP) |
| CI | Card Input |
| CI | Customer Interface |
| CI | Control Instrumentation |
| CI | Coded Information |
| CI | Contour Interval |
| CI | Certification Inspection |
| CI | Christic Institute (Malibu, CA) |
| CI | Commercial Intelligence |
| CI | Circuit Interrupter |
| CI | Commissariat à l'Information du Canada (Office of the Information Commissioner of Canada) |
| CI | Computer Intelligence (Division of Ziff Davis) |
| CI | Critical Intelligence |
| CI | Cluster Interconnect |
| CI | Customer Installation |
| CI | Current Interrupt |
| CI | Counterpart International |
| CI | Comunità Incontro (Italian: community encounter) |
| CI | Critical Item |
| CI | Combat Intelligence |
| CI | Computer Interconnect |
| CI | Cowl Induction |
| CI | Central Index |
| CI | Call Indicator |
| CI | Certificate of Interpretation |
| CI | Connected Intelligence |
| CI | Contextual Inquiry |
| CI | Contract Item |
| CI | Chemical Injection |
| CI | Cognition and Instruction (journal) |
| CI | Compounded Interest |
| CI | Control Indicator |
| CI | Constructive Interference (physics) |
| CI | Chemonics International |
| CI | Computers in Industry (journal) |
| CI | Combat Identification |
| CI | Curriculum Inquiry |
| CI | Central Impression (printing press with only one impression cylander & multiple colors) |
| CI | Circuit Integrity |
| CI | Civilian Instructor (UK Air Cadets) |
| CI | Confidential Intermediary (adoption) |
| CI | Consular Invoice |
| CI | Customer Integration |
| CI | Complexity Index (Indiana school funding formula) |
| CI | Critical Injury |
| CI | Civilian Internee |
| CI | Crazy Ivan (Soviet submarine maneuver) |
| CI | China Airlines - Taiwan (IATA airline code) |
| CI | Content Identifier |
| CI | Cerebral Insufficiency |
| CI | Congestion Indicator (ATMF) |
| CI | Corner Infielder (baseball; 1st or 3rd baseman) |
| CI | Critical Interface |
| CI | Catalogue Item |
| CI | Controlled Irrigation |
| CI | Counselor Intern |
| CI | Carrier Interferometry |
| CI | Command Inspection |
| CI | Colegio de Ingenieros de Chile |
| CI | Critical Indicator |
| CI | Controlled Introduction |
| CI | Carrington Institute (fictional, gaming) |
| CI | Clandestine Industries (band) |
| CI | Criminal Informant |
| CI | Schedule I Controlled Substance (USA) |
| CI | Chassis Interface |
| CI | Craft Interface |
| CI | Crimson Idol (W.A.S.P music album) |
| CI | Critical Instant |
| CI | Containment Integrity |
| CI | Containment Isolation |
| CI | Combat Ineffective |
| CI | Complex Industries (APICS course) |
| CI | Commonweal Institute |
| CI | Configuration Inspection |
| CI | Contents Inventory (insurance) |
| CI | Certified Investigator |
| CI | Course Indicator |
| CI | Call Intercept |
| CI | Capability Increment |
| CI | Chemical Inspectorate (Great Britain) |
| CI | Configuration Identifier |
| CI | Comercializadoras Internacionales (Spanish) |
| CI | Copy Instruction |
| CI | Cambria and Indiana Railroad |
| CI | Coordinating Installation |
| CI | Count Indicator |
| CI | Conducted Interference |
| CI | Cylinder Index |
| CI | Calling Indicator |
| CI | Cryptographic Interface |
| CI | Crew Interface |
| CI | Contract Investigator |
| CI | Comptoir Informatique |
| CI | Codex Iustiniani (Latin: Justinian Codex, Codices And Manuscripts) |
| CI | Client Inquiry |
| CI | Classical Imaging |
| CI | Chemically Induced Mutation |
| CI | Comparison Instruction |
| CI | Cold Insulated |
| CI | Catfish Institute |
| CI | Comité Intertribal (French: Inter-Tribal Committee) |
| CI | Course Invalid (deviation display) |
| CI | Concatenation Indication |
| CI | Caritas Internacionales |
| CI | Commutation Instant |
| CI | Crystallization Index |
| CI | Continuous Interlock |
| CI | Controlled Iteration |
| CI | Color Interior Film |
| CI | Cost Inspector |
| CI | Contrast Irradiance |
| CI | Colonel Irvine Junior High (Calgary, Canada) |
| CI | Class Complexity/Size Due to Inherited Methods |