• The ct ligature
• Carat (purity) (ct), a measure of the purity of gold and platinum alloys
• Carat (mass) (ct), a unit of mass used for measuring gems and pearls
• Cardiothoracic surgery, the field of medicine specializing in chest surgery
• Center tap, a wire that is connected halfway along one of the windings of a transformer, inductor or a resistor
• Centime (ct), French for "cent", used in English in several Francophone countries
• Central Time zone, a time zone in Canada, the United States, and Mexico
• Champions Trophy
• Chemotype (ct.)
• Civil Air Transport IATA code
• Chrono Trigger, a console role-playing game created by Square for the Super NES
• Crazy Taxi (series), a series of driving video games for multiple platforms
• Cognitive therapy
• Combustion turbine, a rotary engine that extracts energy from a flow of combustion gas
• Computed tomography, a.k.a. CAT scan, a medical imaging method
• Compliant Tower, a deepwater offshore oil platform
• Convective temperature
• Counter-terrorism, the practices, tactics, and strategies used by governments and militaries to fight terrorism
• Court/Courtyard, used in a road name to mean courtyard
• Crawler-transporter, a tracked vehicle used to transport the Space Shuttle from Vehicle Assembly Building to Launch Complex 39
• Cryptologic technician, a United States Navy enlisted rating or job specialty
• Critical Thinking
• c't, a German computer magazine, standing for "Computer Technik"
• Transparency (optics) (see-through)
• Cryme Tyme, a professional wrestling stable working for WWE's RAW brand
• Current transformer, a special kind of transformer used in the electrical power industry
• Cody Travers, a video game character
• Intel Ct, a SIMD multithreading programming model developed by Intel
• Honda CT series, a series of Honda bikes
• Contra-terrene a word sometimes used for antimatter

Organizations

• Calgary Transit, the public transit service in Calgary, Alberta, Canada
• Canadian Tire, a Canadian company engaged in retailing, financial services and petroleum
• Central Trains, a former train operating company in the United Kingdom
• Česká televize (ČT), the public television broadcaster in the Czech Republic
• CT (company), a registered agent firm
• Communist Terrorists (also "Charlie Tango"), a term used by the British during the Malayan Emergency to refer to the Malayan Races Liberation Army

Places

• Canton and Enderbury Islands (via obsolete ISO 3166 country code), part of the Phoenix Islands in the Pacific Ocean
• Canterbury, Kent, UK, via UK postcodes
• Cape Town, the legislative capital of South Africa
• Catania, the capital city of the province of Catania, in Sicily, Italy
• Central African Republic (via FIPS Pub 10-4 code and obsolete NATO diagram)
• Connecticut, via United States postal abbreviation