| CNC-maskine | Computer numerical control |
| CNN | CNN |
| CNT | Confederación Nacional del Trabajo |
| Coahuila | Coahuila |
| coating | rivestimento |
| COBOL | COBOL |
| Coca | Erythroxylum coca |
| Coca-Cola | Coca-Cola |
| Coca-slægten | Erythroxylum coca |
| Cochenillelus | Dactylopius coccus |
| Cochise County | Contea di Cochise |
| Cocktail | Cocktail |
| Coco Chanel | Coco Chanel |
| Coconino County | Contea di Coconino |
| Cocosøerne | Isole Cocos |
| Codec | Codec |
| Codex Alexandrinus | Codex Alexandrinus |
| Codex Argenteus | Codex Argenteus |
| Codex Leningradensis | Codex Lenigradensis |
| Codex Sinaiticus | Codex Sinaiticus |
| Codex Vaticanus | Codex Vaticanus |
| Coelacanth | Latimeria |
| Coenraad Jacob Temminck | Coenraad Jacob Temminck |
| Coenzym | Cofattore |
| Cofidis | Cofidis |
| Cogito ergo sum | Cogito ergo sum |
| Cognac | Cognac |
| Coimbra | Coimbra |
| Cojedes | Cojedes |
| Col du Tourmalet | Colle del Tourmalet |
| Cola | Cola |
| Colantonio | Antonio Colantonio |
| Coldplay | Coldplay |
| Coleman Hawkins | Coleman Hawkins |
| colibakterier | colibatteri |
| 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 | Collagene |
| Collatz-formodningen | Congettura di Collatz |
| Colleen McCullough | Colleen McCullough |
| Collision Course | Collision Course |
| Colombe | La Colombe |
| Colombes | Colombes |
| Colombia | Colombia |
| Colombo | Colombo |
| Colorado | Colorado |
| Colorado Avalanche | Colorado Avalanche |
| Colorado River | Colorado |
| Colorado Rockies | Colorado Rockies |
| Colosseum | Colosseo |
| Colossus | Colossus |
| Columbia | Columbia |
| Columbia Records | Columbia Records |
| Columbia University | Columbia University |
| Columbus | Columbus |
| Columbusmodulet | Columbus orbital facility |
| COM | COM |
| COMECON | COMECON |
| Comic Book Guy | Uomo dei fumetti |
| Comino | Comino |
| Commander in Chief | Una donna alla Casa Bianca |
| Commander Keen | Commander Keen |
| Commedia dell'arte | Commedia dell'arte |
| Commerzbank-Arena | Commerzbank-Arena |
| Commerzbank-Tower | Torre della Commerzbank |
| Commewijne | Commewijne |
| Commodore Amiga | Amiga |
| Commodore International | Commodore International |
| Commodus | Commodo |
| Common Intermediate Language | Common Intermediate Language |
| Common Unix Printing System | Common unix printing system |
| Commonrail | Common rail |
| Commonwealth of Nations | Commonwealth delle nazioni |
| Comorerne | Comore |
| Comosøen | Lago di Como |
| Company of Heroes | Company of Heroes |
| Compile time | Compile-time |
| Compiler | Compilatore |
| Compiègne | Compiègne |
| Comptonspredning | Effetto Compton |
| computer | calcolatore |
| Computer aided design | CAD |
| Computer telephony integration | Computer Telephony Integration |
| Computergrafik | Computer grafica |
| Computermus | Mouse |
| Computerprogram | Software |
| Computerprogrammering | Programmazione |
| Computerrollespil | Videogioco di ruolo |
| Computerspil | Videogioco |
| Computervirus | Virus |
| Computus | Calcolo della Pasqua |
| Conakry | Conakry |
| Conan the Barbarian | Conan il barbaro |
| CONCACAF | CONCACAF |
| Concepción | Concepción |
| Concord | Concord |
| Concorde | Concorde |
| Concurrent Versions System | Concurrent Versions System |
| Condoleezza Rice | Condoleezza Rice |
| Condottiere | Compagnia di ventura |
