CA

CA most often refers to:
 * Canada, a country by ISO 3166-1 alpha-2 code
 * California, U.S. state by postal abbreviation

CA or ca may also refer to:

Companies

 * Air China (IATA airline code CA)
 * CA Technologies, a U.S. software company
 * Cayman Airways, a Cayman Islands airline
 * Channel America, a defunct U.S. television network
 * Coal & Allied, Australian mining company
 * Continental Airlines, a U.S. airline
 * Creative Assembly, a PC game developer
 * Crédit Agricole, a major French bank

Government and political

 * Bureau of Consular Affairs, a division of the U.S. Department of State
 * Canadian Alliance, a former Canadian political party
 * Centre Alliance, Australian political party formerly known as Nick Xenophon Team
 * Citizens' Alliance, a political party in Trinidad and Tobago
 * Combined authority, a local government entity in the United Kingdom
 * Commission on Appointments, a body of the Congress of the Philippines
 * Conservatives Abroad, overseas wing of the British Conservative Party
 * Countryside Alliance, a British political organization
 * Court of Appeals
 * Customs Administration, an agency of Taiwan

Schools

 * Canadian Academy, an international school in Kobe, Japan
 * Cary Academy, a private college-preparatory school in Cary, North Carolina, United States
 * Claiborne Academy, a private school in Claiborne Parish, Louisiana, United States
 * Clarksville Academy, a private college-preparatory school in Clarksville, Tennessee, United States
 * Colorado Academy, a private college-preparatory school in Lakewood, Colorado, United States
 * Concord Academy, a private college-preparatory school in Concord, Massachusetts, United States
 * Connections Academy, an online school based in Baltimore, Maryland, United States
 * Culver Academies, a boarding school and summer camp program in Culver, Indiana, United States

In sport

 * California Angels, former name of a professional baseball team currently known as Los Angeles Angels
 * Club Africain, a multi-sport club from Tunis, Tunisia
 * Cricket Australia, the governing body for professional and amateur cricket in Australia
 * Cruising Association, a UK membership organization for sailors
 * Cycling Australia, the national governing body for bicycle racing in Australia

Other organizations

 * Caterers' Association, former UK trade association
 * Cocaine Anonymous, a twelve-step program
 * Creativity Alliance, an arm of Creativity (religion), a white supremacist organization

In linguistics

 * Ca., an abbreviation for circa, meaning "approximately" in Latin
 * Ça, French demonstrative pronoun
 * Ca (Indic), a glyph in the Brahmic family of scripts
 * Ca (Javanese), a letter in the Javanese script
 * Catalan language (ISO 639 alpha-2 language code)
 * ca, the subdomain for Catalan Wikipedia
 * Contrastive analysis, the systematic study of a pair of languages

Biology and medicine

 * CA (journal), a medical journal
 * Ca (moth), a moth genus
 * Ca., abbreviation for Candidatus, for taxonomical names that have not been completely described
 * Cancer
 * Carbonic anhydrase, a family of enzymes
 * Carcinoma, a type of cancer
 * Cardiac arrest

Chemistry

 * Calcium, symbol Ca, a chemical element
 * Catecholamine, an organic compound
 * Cellulose acetate, a type of plastic
 * Chemical Abstracts, a publication of Chemical Abstracts Service
 * Cyanoacrylate, a chemical compound

Mathematics and computing

 * Cellular automaton, a discrete mathematical model
 * Certificate authority, an entity issuing digital certificates for secure communications
 * Correspondence analysis, a multivariate statistical technique
 * Cultural algorithm, a type of evolutionary computation in computer science

Other uses in science and technology

 * Centiampere (cA), an SI unit of electric current
 * Certificate Authority (CA), an entity that issues digital certificates
 * CA-class submarine, a World War II Italian midget submarine
 * Nissan CA engine, used in smaller Nissan vehicles
 * Chromatic aberration, a distortion in optical lenses
 * Conditional access, in broadcast engineering
 * Conservation agriculture, a food system
 * Conversation Analysis, the study of talk in interaction

Places

 * Cả River, in Laos and Vietnam
 * Province of Cádiz, Spain
 * City of Carlisle, United Kingdom, by postcode
 * Catamarca Province, Argentina
 * Central America
 * Tokyo Bay Aqua-Line, a bridge-tunnel across Tokyo Bay area in Japan, numbered as CA

Other uses

 * .ca, Internet country code for Canada
 * CA-, a road designation for highways part of the Central American highway network
 * CA, the official designation for heavy cruiser in the U.S. Navy from 1920–1945
 * 'CA': Tactical Naval Warfare in the Pacific 1941-43, a 1973 board wargame that simulates World War II naval combat
 * Ca Mè Mallorquí, a dog breed native to Spain
 * centiare = 1 square metre
 * Character assassination, a deliberate and sustained effort to damage the reputation or credibility of an individual
 * Chartered Accountant
 * Civil affairs, a term used by both the United Nations and by military institutions
 * Communication arts (disambiguation)
 * Confidentiality agreement
 * Current account (disambiguation), in economics
 * A US Navy hull classification symbol: Heavy cruiser (CA)