| Cilium | Cillian Murphy | Cilostazol |
| Cima Bianca | Cima da Lägh | Cima dal Cantun |
| Cima de Barna | Cima de Gagela | Cima de Nomnom |
| Cima de Pian Guarnei | Cima dei Cogn | Cima del Rosso |
| Cima del Serraglio | Cima dell'Uomo | Cima della Bianca |
| Cima della Bondasca | Cima dello Stagn | Cima di Biasca |
| Cima di Bri | Cima di Broglio | Cima di Castello |
| Cima di Cugn | Cima di Gagnone | Cima di Gana Bianca |
| Cima di Jazzi | Cima di Piancabella | Cima di Pinadee |
| Cima di Rosso | Cima Rossa | Cima Verosso |
| Cimarron (1931 film) | Cimarron (novel) | Cimarron City, Oklahoma |
| Cimarron, Kansas | Cimarron, New Mexico | Cimbri |
| Cimemoxin | Cimetidine | Cimetta |
| Cimex lectularius | Cimicifuga | Cimmerian Plate |
| Cinara | Cinara acutirostris | Cinara alaskana |
| Cinara alba | Cinara arizonica | Cinara atlantica |
| Cinara atripes | Cinara atroalbipes | Cinara azteca |
| Cinara cedri | Cinara cupressi | Cinara glabra |
| Cinara glacialis | Cinara idahoensis | Cinara minuta |
| Cinara montanicola | Cinara nigra | Cinara nigripes |
| Cinara obscura | Cinara oregonensis | Cinara pacifica |
| Cinara piceae | Cinara piceicola | Cinara picta |
| Cinara pilicornis | Cinara piniphila | Cinara pinivora |
| Cinara pulverulens | Cinara radicivora | Cinara rubicunda |
| Cinara sibericae | Cinara sibiricae | Cinara sitchensis |
| Cinara smaragdina | Cinara xylophila | Cinchona |
| Cinchonine | Cinchophen | Cincinnati |
| Cincinnati, Iowa | Cincinnati, Ohio | Cincinnatus, New York |
| Cinclus cinclus | Cinco Paul and Ken Daurio | Cinderella (1950 film) |
| Cinderella (2015 film) | Cinderella II: Dreams Come True | Cindy Crawford |
| Cindy Robinson | Cindy Sheehan | Cinecittà |
| Cinema 4D | Cinema 500 km | Cinema of Argentina |
| Cinema of Brazil | Cinema of Colombia | Cinema of Cuba |
| Cinema of Ecuador | Cinema of India | Cinema of Paraguay |
| Cinema of Peru | Cinema of the United States | Cinema of Uruguay |
| Cinema of Venezuela | Cinema Paradiso | Cinematographer |
| Cinematography | Cinemoz | Cineplexx |
| Cineraria | Cineraria geifolia | Cinereous Vulture |
| Cingulata | Cingulate cortex | Cingulate gyrus |
| CiNii | Cinnabar | Cinnamaldehyde |
| Cinnamic acid | Cinnamomum | Cinnamomum burmanni |
| Cinnamomum burmannii | Cinnamomum camphora | Cinnamomum cassia |
| Cinnamomum citriodorum | Cinnamomum glanduliferum | Cinnamomum loureiroi |
| Cinnamomum osmophloeum | Cinnamomum parthenoxylon | Cinnamomum pedunculatum |
| Cinnamomum tamala | Cinnamomum verum | Cinnamon |
| Cinnamon (software) | Cinnarizine | Cinnyricinclus leucogaster |
| Cinnyris asiaticus | Cinnyris habessinicus | Cinnyris osea |
| Cinnyris oseus/Nectarinia Osea | Cinnyris superbus | Cioteronel |
| Cipher | Ciphertext | Ciphertext-only attack |
| Cipières | Ciprian Deac | Ciprian Marica |
| Ciprian Tătărușanu | Ciprofibrate | Circaea lutetiana |
| Circaetus | Circaetus cinerascens | Circaetus cinereus |
| Circaetus fasciolatus | Circaetus gallicus | Circaetus pectoralis |
| Circassia | Circassian nationalism | Circassians |
| Circe | Circinae | Circle |
| Circle graph | Circle group | Circle of Willis |
| Circle Pines, Minnesota | Circle, Montana | Circleville, Kansas |
| Circleville, Ohio | Circleville, Utah | Circoviridae |
| Circuit breaker | Circuit court | Circuit de la Sarthe |
| Circuit de Nevers Magny-Cours | Circuit design | Circuit Park Zandvoort |
| Circuit Paul Ricard | Circuit reliability | Circuit switching |
| Circuit Switching | Circuit total limitation | Circuito de Jerez |
| Circuito del Jarama | Circular dichroism | Circular Dichroism |
| Circular motion | Circular orbit | Circular sector |
| Circular segment | Circular shift | Circulation (physiology) |
| Circulatory collapse | Circulatory system | Circumcision |
| Circumcision controversy in early Christianity | Circumcision of Jesus | Circumduction (anatomy) |
| Circumference | Circumfix | Circumpolar star |
| Circumscribed circle | Circus aeruginosus | Circus buffoni |
| Circus Charlie | Circus cinereus | Circus cyaneus |
| Circus macrourus | Circus maurus | Circus pygargus |
| Cirebon | Ciriaco de' Pizzicolli | Ciriaco Errasti |
| Ciriaco Sforza | Cirilo Antonio Rivarola | Ciro Capuano |
| Ciro Ferrara | Ciro Immobile | Cirrhosis |
| Cirripedia | Cirrus SR22 | Cirsium |
| Cirsium arvense | Cirsium creticum | Cirsium leucocephalum |
| Cirsium libanoticum | Cirsium syriacus | Cirsium texanum |
| Cirsium tuberosum | Cirsium turkestanicum | Cirsium vinaceum |
| Cirsium vulgare | Cirta | Cis |
| Cis-3-Hexen-1-ol | CISA | Cisalpine Republic |
| Cis–trans isomerism | Cisco ccna | Cisco Express Forwarding |
| Cisco IOS | Cisco Systems | Cisco, Illinois |
| Cisco, Texas | Cisgender | Cisne, Illinois |
| Cisplatin | Cisplatine War | Cissna Park, Illinois |
| Cissus | Cistaceae | Cistanche |
| Cistanche salsa | Cistanche tubulosa | Cisteae |
| Cistern | Cisterns of Tawila | Cisticola juncidis |
| Cistus | Cistus albidus | Cistus ×incanus |
| Cistus creticus | Cistus heterophyllus | Cistus incanus |
| Cistus ladanifer | Cistus libanotis | Cistus monspeliensis |
| Cistus populifolius | Cistus salviifolius | Cisuralian |
| Citadel | Citadel of Erbil | Citadel of the Hồ Dynasty |
| Citation | Cité de l'Architecture et du Patrimoine | Cité de l'espace |
| CITES | Citharexylum | Citharinus |
| Citi | Citibank | Citibank Morocco |
| Cities of Indonesia | Citipati | Citizen journalism |
| Citizen Kane | Citizen science | Citizendium |
| Citizendium.org | Citizenship | Citoyenneté romaine |
| Citrate | Citric acid | Citric acid cycle |
| Citrix Systems | Citroën | Citroën C4 |
