CI or Ci may refer to:

Business terminology

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

Businesses and organisations

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

* Charity Intelligence Canada * China Airlines (IATA code) *

Cigna Cigna is an American multinational managed healthcare and insurance company based in Bloomfield, Connecticut. Its insurance subsidiaries are major providers of medical, dental, disability, life and accident insurance and related products and se ...

health services (NYSE symbol) * Consumers International * Cycling Ireland * CI Records, a music record label *

Cambria and Indiana Railroad The Cambria and Indiana Railroad (C&I) is a railway company that is located in the southeastern part of Indiana County, Pennsylvania in the United States. Incorporated in 1904 and built in 1910 with the intention of carrying lumber, coal was dis ...

* CANZUK International, organisation which promotes cooperation between Canada, Australia, New Zealand and the United Kingdom *

Conservation International Conservation International (CI) is an American nonprofit environmental organization headquartered in Crystal City, Arlington, Virginia. CI's work focuses on science, policy and partnership with businesses, governments and communities. The organ ...

, an international environmental non-governmental organization *

Communications International The Postal, Telegraph and Telephone International (PTTI) was a global union federation bringing together unions of communications workers worldwide. History While a meeting of unions of communication workers was held in Paris in 1911, no lasting o ...

, a former global union federation * Communist International * Children International, a non-profit child sponsorship organization

Law and military

* Counterintelligence * Confidential informant *

Compliance Inspection Unit Compliance Inspection (UCI) is a United States Air Force inspection conducted to assess areas mandated by law, as well as mission areas identified by senior Air Force and Major Command (MAJCOM) leadership as critical or important to the health ...

, a United States Air Force inspection * Chief inspector, a 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

Places

* Ci County, in Hebei, China *

Cayman Islands The Cayman Islands () is a self-governing British Overseas Territory—the largest by population in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac and Little Cayman, which are located to the ...

* Chile (FIPS country code, obsolete NATO country code) *

Coney Island Coney Island is a peninsular neighborhood and entertainment area in the southwestern section of the New York City borough of Brooklyn. The neighborhood is bounded by Brighton Beach and Manhattan Beach, Brooklyn, Manhattan Beach to its east, L ...

* Cocos (Keeling) Islands, an external territory of Australia *

Côte d'Ivoire Ivory Coast, also known as Côte d'Ivoire, officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital is Yamoussoukro, in the centre of the country, while its largest city and economic centre is ...

(ISO country code) * Channel Islands * Channel Islands of California *

Carbonia-Iglesias The province of Carbonia-Iglesias (, ) was a provinces of Italy, province in the autonomous region of Sardinia, Italy. It included the historical area of Sulcis-Iglesiente and it was the smallest province of Sardinia. It is bordered by the provinces ...

, a province in southern Italy

Science, technology and mathematics

Biology and medicine

cI protein Ci protein, short for Cubitus interruptus, is a zinc finger containing transcription factor involved in the Hedgehog signaling pathway. In the absence of a signal to the Hedgehog signaling pathway, the Ci protein is cleaved and destroyed in pr ...

, a repressor protein of ''Enterobacteria phage λ'' * Cytoplasmic incompatibility, a reproductive system * Cardiac index *

Ci protein Ci protein, short for Cubitus interruptus, is a zinc finger containing transcription factor involved in the Hedgehog signaling pathway. In the absence of a signal to the Hedgehog signaling pathway, the Ci protein is cleaved and destroyed in pr ...

, Cubitus interruptus -protein * Coital incontinence * Convergence insufficiency *

Corpulence index The Corpulence Index (CI) (also Ponderal Index (PI) or Rohrer's Index) is a measure of obesity, corpulence, or of leanness in other variants, of a person''Foods and Nutrition Encyclopedia'', Audrey H. Ensminger, Marion Eugene Ensminger. p. 1645 ca ...

* Cumulative incidence, used as a measure of disease frequency in epidemiology * Cochlear implant *

Chemical injury syndrome Multiple chemical sensitivity (MCS), also known as idiopathic environmental intolerances (IEI), is an unrecognized and controversial diagnosis characterized by chronic symptoms attributed to exposure to low levels of commonly used chemicals. Symp ...

, an increased sensitivity to common chemicals also called multiple chemical sensitivity. *

Chronic illness A chronic condition is a health condition or disease that is persistent or otherwise long-lasting in its effects or a disease that comes with time. The term ''chronic'' is often applied when the course of the disease lasts for more than three mo ...

, a condition that is long-lasting or recurrent * Contraindication

Computing

.ci .ci is the Internet country code top-level domain (ccTLD) for Côte d'Ivoire Ivory Coast, also known as Côte d'Ivoire, officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital is Yamousso ...

, 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 In frequentist statistics, a confidence interval (CI) is a range of estimates for an unknown parameter. A confidence interval is computed at a designated ''confidence level''; the 95% confidence level is most common, but other levels, such as 9 ...

, an interval estimate of a population parameter used in statistics *

101 (number) 101 (one hundred ndone) is the natural number following 100 (number), 100 and preceding 102 (number), 102. It is variously pronounced "one hundred and one" / "a hundred and one", "one hundred one" / "a hundred one", and "one oh one". As an Or ...

(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 Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small prop ...

meteorite * Carrier interferometry, a radio and optical communication coding technology *

Chemical ionization Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules (often ...

, 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 Collective intelligence (CI) is shared or group intelligence (GI) that emerges from the collaboration, collective efforts, and competition of many individuals and appears in consensus decision making. The term appears in sociobiology, politic ...

, a subfield of sociology * Colour Index International, a reference database of CI numbers for dyes and pigments *

Bavarian C I Bavarian C Is were steam locomotives with the Royal Bavarian State Railways (''Königlich Bayerische Staatsbahn''). They were the first six-coupled engines in Kingdom of Bavaria, Bavaria and were developed specially for the route between Neuenma ...

, a steam locomotive with the Royal Bavarian State Railways *

Compression ignition engine Compression may refer to: Physical science * Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression *Gas compression * Compression ratio, of a ...

, another name for a diesel engine

Television

* ''

Canadian Idol ''Canadian Idol'' is a Canadian reality television competition show which aired on CTV, based on the British show ''Pop Idol''. The show was a competition to find the most talented young singer in Canada, and was hosted by Ben Mulroney. Jon Dore ...

'', a Canadian television series * '' Law & Order: Criminal Intent'', an American television series *

Crime & Investigation Network Crime & Investigation (stylized as Crime + Investigation) is an American pay television channel owned by A&E Networks, a joint venture between the Hearst Communications and the Disney Media Networks division of The Walt Disney Company. The cha ...

** Crime & Investigation Network (Australia), Australian cable and satellite network focusing on Crime **

Crime & Investigation Network (Europe) Crime & Investigation (stylized as Crime + Investigation) is a pan-European television channel based in the United Kingdom, owned by A&E Networks UK (a joint venture of A&E Networks and Sky Group). The channel primarily broadcasts true crime ...

, a pan-European television channel **

Crime & Investigation Network (South East Asia) Crime & Investigation Network (also known on promotions as "CI" and branded on-air and stylized as "Crime + Investigation") is a Southeast Asian pay television channel which focuses on crime, investigation and mystery programming. It is run by A+E ...

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