CI

Criminology and Military

• Counter-intelligence
• Confidential Information
• Crazy Ivan: a U.S. Navy term for a Soviet submarine maneuver
• Compliance Inspection (USAF)

Finance

• CIGNA, CI is the stock symbol for CIGNA Corporation

Locations and Continental Services

• Cayman Islands
• Chile, FIPS country code and obsolete NATO country code digram
• Cocos Island, off the Republic of Costa Rica
• Cocos (Keeling) Islands, an external territory of Australia
• Christmas Island, an external territory of Australia
• Kiritimati, another island by the name of "Christmas Island" in the Pacific Ocean
• Côte d'Ivoire, ISO country code digram
• The IATA airline designator for China Airlines (Taiwan ROC)
• Cryonics Institute
• Channel Islands
• Qi, in Tongyong Pinyin

Medicine

• Cardiac index
• Ci protein, Cubitus interruptus -protein
• Convergence insufficiency
• Cumulative incidence, used as a measure of disease frequency in epidemiology
• Cochlear implant
• Chemical injury syndrome, an increased sensitivity to common chemicals also called multiple chemical sensitivity.

Philosophy

• Categorical imperative

Politics

• Certificate of identity
• Conservation International
• Civilian Internee, a special status of a prisoner during wartime
• Companion of the Order of the Crown of India, postnominal

Science, Technology and Mathematics

• Computational Intelligence
• Common Interface for a Conditional Access Module.
• CI+, Common Interface Plus
• Continuous integration, a software engineering term.
• Configuration interaction, a post-Hartree-Fock method used in computational chemistry.
• Confidence interval, an interval estimate of a population parameter used in statistics.
• Convective instability
• Curie (Symbol: Ci). A measurement of radioactivity named after Marie Curie.
• Cirrus cloud
• Cosine integral (standard mathematical symbols "Ci" and "ci").
• Confidence interval (statistics).
• CI group, a type of meteorite.
• Core Image
• 101 in Roman numerals.
• Configuration item in Configuration Management.
• Copenhagen Interpretation, an interpretation of Quantum Mechanics.
• Compound Interest (Mathematics)
• cI protein, a repressor protein of Enterobacteria phage λ
• cubic inch, a unit of volume used almost exclusively in the United States.

Television

• Canadian Idol, the Canadian television series.
• Law & Order: Criminal Intent, the television series.
• Crime & Investigation Network (Australia), Australian cable and satellite network focusing on Crime.
• Crime & Investigation Network (UK), United Kingdom cable and satellite network focusing on Crime

Other

• Ci (poetry), a form of Chinese lyric poetry
• Cycling Ireland
• Competitive Intelligence
• Collective intelligence, a subfield of Sociology
• China Airlines
• Corporate identity, a concept in marketing
• CI Records, a record label
• Comprehensible Input