| cirkelslutning | circular argument |
| Cirklens kvadratur | Quadrature of the circle |
| cirkulation i verdenshavene | ocean circulation |
| Cirkulær dikroisme | Circular dichroism |
| cirkulære | circular mail |
| Cirkus | Circus |
| Cirkuskunster | Circus skills |
| cis | C sharp |
| CISC | Complex instruction set computer |
| Cisco Systems | Cisco Systems |
| Cistercienserordenen | Cistercians |
| CISV | CISV |
| CISV International | CISV |
| citat slut | unquote |
| citer | zither |
| CITIC Plaza | CITIC Plaza |
| Citizendium | Citizendium |
| citron | lemon |
| Citrongræs | Southernwood |
| Citronmåler | Brimstone moth |
| citronsommerfugl | brimstone |
| Citronsyre | Citric acid |
| Citronsyrecyklus | Citric acid cycle |
| Citronvand | Lemonade |
| Citroën | Citroën |
| Citroën C-Cactus | Citroën c-cactus |
| Citroën C-Metisse | Citroën C-Métisse |
| Citroën DS | Citroën DS |
| Citroën Méhari | Citroën Méhari |
| Citroën XM | Citroën XM |
| Citrus | Citrus |
| Città di Castello | Città di Castello |
| City of Edinburgh | City of Edinburgh |
| City of God | City of God |
| City of Heroes | City of Heroes |
| City of London | City of London |
| Ciudad Guatemala | Guatemala City |
| Ciudad Juárez | Ciudad Juárez |
| civil | civil |
| civil luftfart | civil air traffic |
| Civil religion | Civil religion |
| civilbefolkningens sikkerhed | civil safety |
| civilbeskyttelse | civilian protection |
| Civilisation | Civilization |
| civilisering | civilization |
| Civilization | Civilization |
| civilret | civil law |
| Civiløkonom | Siviløkonom |
| CJD | Creutzfeldt-Jakob disease |
| CKY | CKY |
| Clairauts sætning | Symmetry of second derivatives |
| Claire Littleton | Claire Littleton |
| Clairvaux | Clairvaux Abbey |
| clairvoyance | clairvoyance |
| clairvoyant | clairvoyant |
| Clanbase | ClanBase |
| Clancy Wiggum | Clancy Wiggum |
| Clara | Clara |
| Clara af Assisi | Clare of Assisi |
| Clara Bow | Clara Bow |
| Clara Schumann | Clara Schumann |
| Clara Zetkin | Clara Zetkin |
| Clarence Melvin Zener | Clarence Zener |
| Clarence Seedorf | Clarence Seedorf |
| Clarinetist | Klarinetist |
| Clark Gable | Clark Gable |
| Claude Adrien Helvétius | Claude Adrien Helvétius |
| Claude Chabrol | Claude Chabrol |
| Claude Criquielion | Claude Criquielion |
| Claude Debussy | Claude Debussy |
| Claude Jade | Claude Jade |
| Claude Monet | Claude Monet |
| Claudia Cardinale | Claudia Cardinale |
| Claudio Monteverdi | Claudio Monteverdi |
| Claudius | Claudius |
| Claudius II | Claudius II |
| Claus von Stauffenberg | Claus Schenk Graf von Stauffenberg |
| Clavicula | Clavicle |
| Claviorganum | Claviorganum |
| Clayton Conrad Anderson | Clayton Anderson |
| Clemens af Alexandria | Clement of Alexandria |
| Clemens Brentano | Clemens Brentano |
| Clement Attlee | Clement Attlee |
| Clementine-missionen | Clementine probe |
| Cleopatra Selene | Cleopatra Selene II |
| Clermont-Ferrand | Clermont-Ferrand |
| Cletus Spuckler | Cletus Spuckler |
| Cleveland | Cleveland |
| Cleveland Abbe | Cleveland Abbe |
| Cleveland Browns | Cleveland Browns |
| Cleveland Indians | Cleveland Indians |
| Click Here to Exit | Click Here to Exit |
| Cliff Burton | Cliff Burton |
| Cliff Richard | Cliff Richard |
| Cliffony | Cliffoney |
| Clint Eastwood | Clint Eastwood |
| Clinton | Clinton |
| Clips | Trombone |
| CLIPSAS | CLIPSAS |
| Clive Owen | Clive Owen |
| Clive Sinclair | Clive Sinclair |
| Clivia | Clivia |
| Clodomer | Chlodomer |
| Clone Wars | The Clone Wars |
| Clonmel | Clonmel |
| Cloud City | Cloud City |
| cloudcomputing | cloud computing |
| Cloudsat | CloudSat |
| Clube de Regatas do Flamengo | Clube de Regatas do Flamengo |
| Cluedo | Cluedo |
| Cluj | Cluj County |
| Cluj-Napoca | Cluj-Napoca |
| Cluny | Cluny Abbey |
| Clyde Tombaugh | Clyde Tombaugh |
| Clymenedelfin | Clymene Dolphin |
| Clásica de San Sebastián | Clásica de San Sebastián |
| Clément Janequin | Clément Janequin |
| CMAS | Confédération Mondiale des Activités Subaquatiques |
| CMRR | Common-mode rejection ratio |
| CMYK | CMYK color model |
| CN Tower | CN Tower |
| CNC-maskine | CNC |
| CNE | National Electoral Council |
| CNN | CNN |
| CNT | Confederación Nacional del Trabajo |
| Coahuila | Coahuila |
| coating | coating |
| COBOL | COBOL |
| Coca | Coca |
| Coca-Cola | Coca-Cola |
| Coca-familien | Erythroxylaceae |
| Coca-slægten | Erythroxylum |
| Cockcroft-Walton generator | Cockcroft-Walton generator |
| Cockerspaniel | English Cocker Spaniel |
| Cocktail | Cocktail |
| Coco Chanel | Coco Chanel |
| Cocosøerne | Cocos Islands |
| Code talker | Code talker |
| Codex Alexandrinus | Codex Alexandrinus |
| Codex Argenteus | Codex Argenteus |
| Codex Gigas | Codex Gigas |
| Codex Leningradensis | Leningrad Codex |
| Codex Sinaiticus | Codex Sinaiticus |
| Codex Vaticanus | Codex Vaticanus |
| Coenraad Jacob Temminck | Coenraad Jacob Temminck |
| Cofidis | Cofidis |
| Cogito ergo sum | Cogito ergo sum |
| Cognac | Cognac |
| Coimbra | Coimbra |
| Coitus reservatus | Coitus reservatus |
| Cojedes | Cojedes |
| Col du Tourmalet | Col du Tourmalet |
| Cola | Cola |
| Colantonio | Niccolò Antonio Colantonio |
| Colchester | Colchester |
| Cold open | Cold open |
| Coldplay | Coldplay |
| Coleman Hawkins | Coleman Hawkins |
| colibakterier | coliform bacterium |
| Colima | Colima |
| Colin Farrell | Colin Farrell |
| Colin Firth | Colin Firth |
| Colin Greenwood | Colin Greenwood |
| Colin Maclaurin | Colin Maclaurin |
| Colin McRae | Colin McRae |
| Colin Powell | Colin Powell |
| Collage | Collage |
| Collagen | Collagen |
| Collatz-formodningen | Collatz conjecture |
| Colleen McCullough | Colleen McCullough |
| collie | collie |
| Colombe | La Colombe |
| Colombes | Colombes |
| Colombia | Colombia |
| Colombo | Colombo |
| Colonel Sun | Colonel Sun |
| Colorado | Colorado |
| Colorado Avalanche | Colorado Avalanche |
| Colorado River | Colorado River |
| Colorado Rockies | Colorado Rockies |
| Colosseum | Colosseum |
| Colossus | Colossus computer |
| Colt Canada | Diemaco |
| Columbia | Columbia |
| Columbia Records | Columbia Records |
| Columbia University | Columbia University |
| Columbus | Columbus |
| Columbus Blue Jackets | Columbus Blue Jackets |
| Columbusmodulet | Columbus |
| COM | Com |
| COMECON | Comecon |
| Comic Book Guy | Comic Book Guy |
| Comino | Comino |
| Commandant of the Marine Corps | Commandant of the Marine Corps |
| Commander Keen | Commander Keen series |
| Commedia dell'arte | Commedia dell'arte |
| Commerzbank-Arena | Commerzbank-Arena |
| Commerzbank-Tower | Commerzbank Tower |
| Commewijne | Commewijne District |
| Commodore Amiga | Amiga |
| Commodore International | Commodore International |
| Commodus | Commodus |
| Common Intermediate Language | Common Intermediate Language |
| Common Unix Printing System | Common Unix Printing System |
| Commonwealth of Nations | Commonwealth of Nations |
| Comorerne | Comoros |
| Comosøen | Lake Como |
| Company of Heroes | Company of Heroes |
| Compiler | Compiler |
| Compiègne | Compiègne |
| Comptonspredning | Compton scattering |
| computer | computer |
| Computer aided design | Computer-aided design |
| Computeranimationsfilm | List of computer-animated films |
| Computergrafik | Computer graphics |
| Computermus | Mouse |
