Organizations

• Canadian Interuniversity Sport
  Canadian Interuniversity Sport
  Canadian Interuniversity Sport is the national governing body of university sport in Canada, comprising the majority of degree granting universities in the country. Its equivalent body for organized sports at colleges in Canada is The Canadian Colleges Athletic Association...
  
  , the national governing body of university sport in Canada
• Center for Immigration Studies
  Center for Immigration Studies
  The Center for Immigration Studies is a non-profit research organization that advocates Immigration reduction in the United States. Founded in 1985, its executive director is Mark Krikorian. As a 501 organization, it is subject to limits or absolute prohibitions on engaging in political...
  
  , a research organization in Washington, DC
• Centre for Independent Studies
  Centre for Independent Studies
  The Centre for Independent Studies is a libertarian think tank founded in April 1976 by Executive Director Greg Lindsay. The CIS is one of six think tanks recognised by the National Institute for Research Advancement in Tokyo, Japan...
  
  , a libertarian think tank in Australia
• Christians in Science
  Christians in Science
  Christians in Science is a British organization of scientists, philosophers, theologians, ministers, teachers, and science students, predominantly evangelical Christians, concerned with the dialogue between Christianity and science...
  
  , professional organization for scientists who are Christians
• Commonwealth Investigation Service, an intelligence organization founded in 1916, and gradually subsumed by ASIO
  Australian Security Intelligence Organisation
  The Australian Security Intelligence Organisation is Australia's national security service, which is responsible for the protection of the country and its citizens from espionage, sabotage, acts of foreign interference, politically-motivated violence, attacks on the Australian defence system, and...
  
   by 1960
• Council for International Service (1919–1927), an organization of Quakers based in Britain

Medicine and health

• Cancer Information Service
  Cancer Information Service
  The Cancer Information Service is a program of the National Institutes of Health that is provided to the United States of America public to provide personalized, confidential responses to specific questions about cancer...
  
  , a public and personalized information service in the United States
• Carcinoma in situ
  Carcinoma in situ
  Carcinoma in situ is an early form of cancer that is defined by the absence of invasion of tumor cells into the surrounding tissue, usually before penetration through the basement membrane. In other words, the neoplastic cells proliferate in their normal habitat, hence the name "in situ"...
  
  , an early form of malignant cancer
• Clinically isolated syndrome
  Clinically isolated syndrome
  A clinically isolated syndrome is an individual's first neurological episode, caused by inflammation or demyelination of nerve tissue...
  
  , an initial neurological episode related to nerve tissue
• Clinical information system, an information system designed to manage clinical aspects of a hospital
• Critical incident stress, a post-traumatic stress disorder
• Combined intracavernous injection and stimulation test
  Combined intracavernous injection and stimulation test
  Combined intracavernous injection and stimulation test or CIS test is the most commonly performed office diagnostic procedure for erectile dysfunction. It consists of an intracavernosal injection, visual or manual sexual stimulation, and a rating of the subsequent erection...
  
  , a diagnostic procedure for erectile dysfunction

Computing and technology

• Card Information Structure, formatting and organization data stored on a PC card
• Comodo Internet Security
  Comodo Internet Security
  Comodo Internet Security , developed by Comodo Group, is an Internet security suite available for Microsoft Windows. It offers anti-malware protection, a personal firewall, a sandbox and a Host-based Intrusion Prevention System called Defense+.-Editions:Comodo Internet Security is available in...
  
  , a freeware security suite developed by Comodo
• CompuServe Information Service, a commercial online service in the United States
• Computer information systems, a digital management information system
• Contact image sensor
  Contact Image Sensor
  Contact Image Sensors are a relatively recent technological innovation in the field of optical flatbed scanners that are rapidly replacing CCDs in low power and portable applications...
  
  , technology developed for optical flatbed scanners
• Continuous ink system
  Continuous ink system
  A continuous ink system , also known as a continuous ink supply system , a continuous flow system , an automatic ink refill system , a bulk feed ink system, or an off-axis ink delivery system is a method for delivering a large and practically unlimited volume of liquid ink to a comparatively small...
  
  , a cost-effective replacement for ink-jet printer cartridges
• Continuous integration server, a server computer used for software engineering and development
• Customer information system, used to help manage customer relationships

Schools and education

• Chinese International School
  Chinese International School
  Chinese International School is a private school offering the years Reception-Year 13 in Hong Kong. It is famous for its bilingual programme taught in English and Chinese , outstanding academic programme and excellent matriculation. Students come from diverse backgrounds, with over 30...
  
  , a private Reception-Year 13 (K-12) school in Hong Kong
• Clifford International School
  Clifford International School
  The Clifford International School is an international school located in Guangzhou, People's Republic of China. The school follows the Canadian curriculum, which more precisely, the study programs of the province of Manitoba...
  
  , a K-12 international school following the Canadian curriculum in Guangzhou, China
• Colombo International School
  Colombo International School
  Colombo International School is a co-educational independent day-school in Colombo, Sri Lanka. There are 1400 enrolled students from 30 countries, ranging from 3 to 19 years in the Infant, Junior and Secondary sections.-History:...
  
  , in the suburbs of Colombo, Sri Lanka
• College in the Schools
  College in the Schools
  College in the Schools is an educational program for high school students run by the University of Minnesota. It allows students to take college level classes in their high school and, as a result, earn college and high school credit for free. The classes are taught by high school teachers who...
  
  , an educational program for high school students run by the University of Minnesota
• Communities In Schools
  Communities In Schools
  The Communities In Schools network is a federation of independent 501 organizations in 27 states and the District of Columbia that work to address the dropout epidemic. The organization identifies and mobilizes existing community resources and fosters cooperative partnerships for the benefit of...
  
  , a federation of independent organizations focused on education in United States
• Copenhagen International School
  Copenhagen International School
  Copenhagen International School is an international, co-educational day school located in Hellerup, a suburb of Copenhagen, Denmark. The student body consists of around 600 members representing over 50 different nationalities with English as the primary language of instruction...
  
  , in Hellerup, Copenhagen
• Council of International Schools
  Council of International Schools
  The Council of International Schools is a non-profit association of international schools and post-secondary institutions which aims to improve international education...
  
  , an association of international schools that aims to improve international education
• Cebu International School
  Cebu International School
  Cebu International School, founded as the American International School of Cebu in 1924, the school was renamed in 1973. It is a co-educational day school, non-profit, non-sectarian institution, governed by a ten-member Board of Trustees...
  
  , Philippines

Science

• Common Intelligibility Scale, a reference scale for measuring speech intelligibility
• Configuration interaction singles, a variational quantum-chemical method for calculating excited states
• Copper indium selenide (CuInSe₂), a chemical substance used in solar cells and semiconductors

Miscellaneous

• Canton Island Airport
  Canton Island Airport
  Canton Island Airport is an airport located on Kanton Island, in the Phoenix Islands, in the Republic of Kiribati. It has no commercial airline service.-History:...
  
   (IATA code), an airport located on Kanton Island, in the Phoenix Islands, in the Republic of Kiribati
• Case Information Statement
  Case Information Statement
  A Case Information Statement is a document which is filed with a court clerk at the commencement of a civil lawsuit in many of the court systems of the United States. It is generally filed along with the complaint...
  
  , a document used in civil lawsuits in the United States
• Cisalpino
  Cisalpino
  Cisalpino AG was a railway company operating international trains between Switzerland and Italy connecting Basel, Schaffhausen, Zürich, Geneva, Milan, Venice, Trieste, Livorno, and Florence...
  
  , a railway company operating trains between Switzerland and Italy, referred to as CIS in timetables
• Citizenship and Immigration Services, a bureau in the United States Department of Homeland Security
• Collective investment scheme
  Collective investment scheme
  A collective investment scheme is a way of investing money alongside other investors in order to benefit from the inherent advantages of working as part of a group...
  
  , a scheme for people to invest together for a common goal
• Community Innovation Survey
  Community Innovation Survey
  The Community Innovation Surveys are a series of surveys executed by national statistical offices throughout the European Union and in Norway and Iceland. The harmonized surveys are designed to give information on the innovativity of different sectors and regions...
  
  , a series of surveys throughout the European Union
• Confederacy of Independent Systems, a fictional combatant in the Clone Wars from Star Wars
• Continuous Injection System, a fuel injection system developed by the Robert Bosch Group
• Co-operative Insurance Society, a British insurance company
  • CIS Tower
    CIS Tower
    The Co-operative Insurance Tower, or CIS Tower, is an office tower building on Miller Street in Manchester, England. It was completed in 1962 and rises to 387 feet in height. The Grade II listed building, which houses Co-operative Financial Services, a part of The Co-operative Group, is...
    
    , a building in Manchester, England
• Cubic inch per second, a measure of flow rate
• Current Index to Statistics
  Current Index to Statistics
  The Current Index to Statistics is an online database published by the Institute of Mathematical Statistics and the American Statistical Association that contains bibliographic data of articles in statistics, probability, and related fields....
  
  , a search engine for the statistics literature