CI

CI or Ci, but not C I or C.I, may refer to:

Business

• Customer Intelligence, a discipline in marketing
• Competitive intelligence
• Corporate identity
• Continual improvement
• Custom Install
• China Airlines
• The NYSE symbol for CIGNA Corporation

Criminology and military

• Counterintelligence
• Confidential informant
• Compliance Inspection (USAF)
• Chief Inspector, a police rank

Education

• Channel Islands High School
• California State University Channel Islands

Locations and continental services

• Ci County, in Hebei, China
• Cayman Islands
• Chile, FIPS country code and obsolete NATO country code digram
• Coney Island
• Cocos (Keeling) Islands, an external territory of Australia
• Côte d'Ivoire, ISO country code digram
  • .ci, the Internet country code top-level domain (ccTLD) for Côte d'Ivoire
• The IATA airline designator for China Airlines (Taiwan ROC)
• Channel Islands
• Channel Islands of California
• Qi, in Tongyong Pinyin
• Carbonia-Iglesias, a province in southern Italy

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
• Communist International

Religion

• Josephites of Belgium (Catholic congregation)
• Christian Identity

Science, technology and mathematics

• Carrier interferometry, a radio and optical communication coding technology
• Chemical ionization
• Configuration interaction, a post-Hartree–Fock method used in computational chemistry
• Conservation International, an international environmental non-governmental organization
• Collective intelligence, a subfield of sociology

Computing

• CodeIgniter, a PHP framework (see EllisLab#CodeIgniter)
• 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

Astronomy and meteorology

• CI group, a type of meteorite.
• Cirrus cloud
• Convective instability

Physics

• Conical intersection, the location of a discrete degeneracy between two electronic states
• Curie (Symbol: Ci). A measurement of radioactivity named after Marie Curie
• Copenhagen Interpretation, an interpretation of Quantum Mechanics.

Mathematics and measurement

• 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 (in Roman numerals)
• Compound interest (mathematics)
• cubic inch, a unit of volume used almost exclusively in the United States of America
• Cosine integral (standard mathematical symbols "Ci" and "ci")

Biology and medicine

• cI protein, a repressor protein of Enterobacteria phage λ
• Cytoplasmic incompatibility, a reproductive system
• Cardiac index
• Ci protein, Cubitus interruptus -protein
• 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

Television

• Canadian Idol, the Canadian television series.
• Law & Order: Criminal Intent, the television series.
• Crime & Investigation Network
  • 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
  • Crime & Investigation Network (South East Asia)

Arts

• Ci (poetry), a form of Chinese lyric poetry
• CI Records, a music record label

Other uses

• Cambria and Indiana Railroad
• Categorical imperative, in philosophy
• Ci, common form of the surname Qi from Tungusic peoples
• Civilian Instructor, an adult volunteer in the British Air Cadet Organisation
• Collegium Invisibile
• C.I., Colour Index International
• Comprehensible Input
• Confucius Institute
• Consumers International
• Contact improvisation
• Cycling Ireland