| cinético | kinetic |
| Ciompi | Ciompi |
| Ciorbă | Ciorbă |
| Ciordia | Ziordia |
| cipayo | sepoy |
| Cipetes I de Bitinia | Zipoites I of Bithynia |
| Cipher Pol | Cipher Pol |
| Cipolletti | Cipolletti |
| cipote | dick |
| Cipria | Cypria |
| Ciprian Marica | Ciprian Marica |
| Cipriano Castro | Cipriano Castro |
| Cipriano de Cartago | Cyprian |
| Cipriano de Rore | Cipriano de Rore |
| Cipriano Mera Sanz | Cipriano Mera |
| ciprés | cypress |
| Cipselo | Cypselus |
| CipSoft GmbH | CipSoft GmbH |
| Circaeaster agrestis | Circaeaster agrestis |
| Circaetinae | Circaetinae |
| Circe | Circe |
| Circinus | Circinus |
| Circle Line | Circle line |
| circo | circus |
| Circo de Gavarnie | Cirque de Gavarnie |
| Circo Máximo | Circus Maximus |
| Circo romano | Circus |
| circona | zirconia |
| circona cúbica | cubic zirconia |
| circonato | zirconate |
| circonio | zirconium |
| circuir | bypass |
| Circuit de Spa-Francorchamps | Circuit de Spa-Francorchamps |
| Circuit Gilles Villeneuve | Circuit Gilles Villeneuve |
| Circuit RC | RC circuit |
| circuitería | circuitry |
| circuito | circuit |
| Circuito analógico | Analogue electronics |
| Circuito callejero de Adelaida | Adelaide Street Circuit |
| Circuito callejero de Phoenix | Phoenix street circuit |
| Circuito de Cataluña | Circuit de Catalunya |
| Circuito de Estambul | Istanbul Park |
| Circuito de Fiorano | Fiorano Circuit |
| Circuito de Indianápolis | Indianapolis Motor Speedway |
| Circuito de la Sarthe | Circuit de la Sarthe |
| Circuito de Monjuich | Montjuïc circuit |
| Circuito de Montjuïc | Montjuïc circuit |
| Circuito de Mónaco | Circuit de Monaco |
| Circuito de Nevers Magny-Cours | Circuit de Nevers Magny-Cours |
| Circuito de Papez | Papez circuit |
| Circuito de Pedralbes | Pedralbes Circuit |
| Circuito de Silverstone | Silverstone Circuit |
| Circuito de Suzuka | Suzuka Circuit |
| Circuito de vía | Track circuit |
| Circuito de Zandvoort | Circuit Park Zandvoort |
| Circuito del Distrito de Columbia de Cortes de Apelaciones de Estados Unidos | United States Court of Appeals for the District of Columbia Circuit |
| Circuito del Jarama | Circuito Permanente Del Jarama |
| Circuito eléctrico | Electrical network |
| Circuito integrado | Integrated circuit |
| Circuito Internacional de Bahréin | Bahrain International Circuit |
| Circuito Internacional de Sepang | Sepang International Circuit |
| Circuito Internacional de Shanghai | Shanghai International Circuit |
| Circuito paralelo | Series and parallel circuits |
| Circuito Paul Ricard | Circuit Paul Ricard |
| Circuito Permanente de Alta Velocidad de Jerez | Circuito Permanente de Jerez |
| Circuito regenerativo | Regenerative circuit |
| Circuito resonante | RLC circuit |
| Circuito Ricardo Tormo | Circuit de Valencia |
| Circuito serie | Series and parallel circuits |
| Circuito urbano de Valencia | Valencia Street Circuit |
| circuitos eléctricos | wiring |
| circulacion | traffic |
| circulación | circulation |
| circulación atmosférica | atmospheric circulation |
| Circulación coronaria | Coronary circulation |
| circulación oceánica | ocean circulation |
| Circulación termohalina | Thermohaline circulation |
| Circulan rumores de que Fidel Castro está muerto | Rumors say Cuban President Fidel Castro has died |
| circulante | circulating |
| circular | circular |
| circularr | circulate |
| circulatorio | circulatory |
| circulen | go on |
| circulo | union |
| circumvalar | circumvent |
| Circuncentro | Circumscribed circle |
| circuncidado | circumcised |
| circuncidar | circumcise |
