| clue | indicación |
| Cluedo | Clue |
| Clugin | Clugin |
| Cluj | Cluj |
| Cluj County | Cluj |
| Cluj-Napoca | Cluj-Napoca |
| Cluj-Napoca Botanical Garden | Jardín Botánico de Cluj-Napoca |
| clump | terrón |
| clumsiness | torpeza |
| clumsy | desgraciado |
| clumsy person | torpe |
| Cluniac Order | Orden de Cluny |
| Cluniac Reforms | Orden de Cluny |
| Cluny | Cluny |
| Cluny Abbey | Abadía de Cluny |
| Clupeidae | Clupeidae |
| Clupeiformes | Clupeiformes |
| Clurichaun | Clurichaun |
| Clusiaceae | Clusiaceae |
| cluster | aglomerar |
| cluster bomb | bomba de racimo |
| Cluster chemistry | Cluster |
| Cluster mission | Misión Cluster |
| Cluster of differentiation | Cúmulo de diferenciación |
| Cluster of galaxies | Agrupaciones galácticas |
| Cluster parallax | Paralaje de agrupación |
| Cluster point | Punto de acumulación |
| Cluster rotation | Rotación de cúmulo |
| Cluster type variable star | Estrella variable de cúmulo |
| clustered | en racimo |
| clustering | grupo |
| Clusters of galaxies | Agrupaciones galácticas |
| clutch | asir |
| clutch at | agarrar |
| clutch bag | bolso de mano |
| Clutha River | Río Clutha |
| clutter | lío |
| clutter up | embrollar |
| cluttered | repleto |
| Clyde | Río Clyde |
| Clyde Donovan | Río Clyde |
| Clyde Tombaugh | Clyde Tombaugh |
| Clymene | Clímene |
| Clytemnestra | Clitemnestra |
| Clytie | Clitia |
| Clàrsach | Arpa celta |
| Clásica de San Sebastián | Clásica de San Sebastián |
| Clásico de Avellaneda | Clásico de Avellaneda |
| Cláudio Ibrahim Vaz Leal | Branco |
| Cláudio Santoro | Cláudio Santoro |
| Cláudio Taffarel | Cláudio Taffarel |
| Cléber Santana Loureiro | Cléber Santana |
| Clémence Poésy | Clémence Poésy |
| Clément Janequin | Clément Janequin |
| Clément Marot | Clément Marot |
| Cléo de Mérode | Cléo de Mérode |
| CM Peralta | Club Multideporte Peralta |
| CM Punk | Phil Brooks |
| CML | LMC |
| CMOS | Tecnología CMOS |
| CMYK | Modelo de color CMYK |
| CMYK color model | Modelo de color CMYK |
| CN | CN |
| CN gas | Gas CN |
| CN star | Estrella CN |
| CN Tower | Torre CN |
| CNC | CNC |
| CNES | CNES |
| CNG | GNC |
| Cnicus | Cnicus benedictus |
| Cnidaria | Cnidaria |
| cnidocyte | cnidocito |
| CNN | CNN |
| CNO | CNO |
| CNO anomaly | Anomalía en CNO |
| CNO cycle | Ciclo CNO |
| CNS | SNC |
| CO | Como |
| co-brother-in-law | concuñado |
| co-ed | mixto |
| co-education | coeducación |
| co-educational | mixto |
| Co-evolution | Coevolución |
| co-father-in-law | consuegro |
| co-husband | coesposo |
| co-incineration | co-incineración |
| co-locate | colocar |
| co-mother-in-law | consuegra |
| Co-NP | Co-NP |
| Co-NP-complete | Co-NP-completo |
| co-op | cooperativa |
| co-operate | colaborar |
| co-operation | colaboración |
| co-operation policy | politíca de cooperación |
| co-operation principle | principio de cooperación |
| co-operative | cooperativa |
| Co-operative Party | Co-operative Party |
| co-operator | auxiliar |
| co-opt | cooptar |
