CI

CI or Ci may refer to:

Business terminology

 * Commercial invoice
 * Competitive intelligence
 * Confidential information
 * Continual improvement
 * Corporate identity
 * Customer intelligence, a discipline in marketing

Academia and education

 * California State University, Channel Islands
 * Channel Islands High School
 * Collegium Invisibile
 * Confucius Institute

Religion

 * Josephites of Belgium, a Catholic congregation
 * Christian Identity
 * Christian Institute, a British charity which promotes Christian values

Other businesses and organizations

 * CI Financial, Canadian investment management company
 * Charity Intelligence Canada
 * China Airlines (IATA code)
 * Cigna health services (NYSE symbol)
 * Consumers International
 * Cycling Ireland
 * CI Records, a music record label
 * Cambria and Indiana Railroad
 * CANZUK International, organisation which promotes cooperation between Canada, Australia, New Zealand and the United Kingdom
 * Conservation International, an international environmental non-governmental organization
 * Communications International, a former global union federation
 * Communist International
 * Children International, a non-profit child sponsorship organization

Law and military

 * Counterintelligence
 * Confidential informant
 * Compliance Inspection, a United States Air Force inspection
 * Chief inspector, a police rank
 * Circle inspector, a junior police rank
 * Certificate of identity
 * Civilian Internee, a special status of a prisoner during wartime
 * Civilian Instructor, an adult volunteer in the British Air Training Corps and Canada Air Cadets

Places

 * Ci County, in Hebei, China
 * Cayman Islands
 * Chile (FIPS country code, obsolete NATO country code)
 * Coney Island
 * Cocos (Keeling) Islands, an external territory of Australia
 * Cook Islands, an island-country in the South Pacific Ocean
 * Côte d'Ivoire (ISO country code)
 * Channel Islands
 * Channel Islands of California
 * Carbonia-Iglesias, a province in southern Italy
 * Central India, region of India, abbreviated CI
 * Central India Circuit or C. I. Circuit, a Hindi film distribution circuit comprising parts of Madhya Pradesh (Indian state within central India)

Biology and medicine

 * cI protein, a repressor protein of Enterobacteria phage λ
 * Cytoplasmic incompatibility, a reproductive system
 * Cardiac index
 * Ci protein, Cubitus interruptus -protein
 * Coital incontinence
 * Convergence insufficiency
 * Corpulence index
 * 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.
 * Chronic illness, a condition that is long-lasting or recurrent
 * Contraindication

Computing

 * .ci, the Internet country code top-level domain (ccTLD) for Côte d'Ivoire
 * Common Interface, for a Conditional Access Module
 * CI+, Common Interface Plus
 * Computational intelligence
 * Configuration item, the fundamental structural unit of a configuration management system
 * Core Image, non-destructive image processing technology
 * Continuous integration, a software-engineering practice of merging developer code into a main code base frequently
 * CodeIgniter, a PHP framework

Earth science

 * Cirrus cloud
 * Convective instability

Mathematics

 * Conditional independence, a type of relation of random variables in probability theory
 * Confidence interval, an interval estimate of a population parameter used in statistics
 * 101 (number) (in Roman numerals)
 * Compound interest
 * Cosine integral (standard mathematical symbols "Ci" and "ci")

Physics

 * Conical intersection, the location of a discrete degeneracy between two electronic states
 * Curie (unit) (Symbol: Ci), a measurement of radioactivity named after Marie Curie
 * Copenhagen interpretation, an interpretation of quantum mechanics
 * Cubic inch, a unit of volume

Other uses in science and technology

 * CI group, a type of carbonaceous chondrite meteorite
 * Carrier interferometry, a radio and optical communication coding technology
 * Chemical ionization, a technique used in mass spectrometry
 * Configuration interaction, a post-Hartree–Fock method used in computational chemistry
 * Contextual inquiry, a user-centered design research method
 * Collective intelligence, a subfield of sociology
 * Colour Index International, a reference database of CI numbers for dyes and pigments
 * Bavarian C I, a steam locomotive with the Royal Bavarian State Railways
 * Compression ignition engine, another name for a diesel engine

Television

 * Canadian Idol, a Canadian television series
 * Law & Order: Criminal Intent, an American television series
 * Crime & Investigation Network
 * Crime & Investigation Network (Australia), Australian cable and satellite network focusing on Crime
 * Crime & Investigation Network (Europe), a pan-European television channel
 * Crime & Investigation Network (South East Asia)

Other uses

 * Ci (poetry), a form of Chinese lyric poetry
 * Qi, a central concept in several eastern philosophies
 * Categorical imperative, in philosophy
 * Colour Index International, a reference database
 * Comprehensible input
 * Contact improvisation, a dance technique
 * CI, postnominal for Companion of the Order of the Crown of India
 * Ci, a form of the surname Qi, of the Tungusic peoples