| 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 | Citron |
| Citrullus | Citrullus colocynthis | Citrullus lanatus |
| Citrus | Citrus aurantiifolia | Citrus aurantium |
| Citrus × paradisi | Citrus ×aurantifolia | Citrus ×aurantium |
| Citrus ×bergamia | Citrus ×clementina | Citrus ×limon |
| Citrus ×paradisi | Citrus ×sinensis | Citrus ×tangerina |
| Citrus clementina | Citrus greening disease | Citrus japonica |
| Citrus limettioides | Citrus maxima | Citrus medica |
| Citrus medica var. sarcodactylis | Citrus production | Citrus psorosis virus |
| Citrus reticulata | Citrus reticulata × sinensis | Citrus tangerina |
| Citrus tristeza virus | Cittaslow | City |
| City bicycle | City block | City car |
| City Connection | City designated by government ordinance | City Football Group |
| City Hunter | City life (لعبة) | City Life (video game) |
| City Lights | City Manager | City marketing |
| City network | City of Arts and Sciences | City of Ember |
| City of God (2002 film) | City of Life | City of Life and Death |
| City of London | City of Manchester Stadium | City of the Dead (Cairo) |
| City Point, Wisconsin | City Protocol | City Slickers |
| City University London | City University of New York | City wiki |
| City Year | City-building game | City-state |
| Ciutat de Palma | Civetone | CIVETS |
| Civettictis civetta | Civic intelligence | Civic political culture |
| Civics | Civil and political rights | Civil authority |
| Civil aviation | Civil Aviation Administration of China | Civil Aviation Affairs |
| Civil Aviation and Meteorological Authority of Yemen | Civil Aviation Authority (United Kingdom) | Civil code |
| Civil discourse | Civil disobedience | Civil engineering |
| Civil Guard (Spain) | Civil law (legal system) | Civil liberties |
| Civil registry | Civil rights referendum | Civil society |
| Civil uprising phase of the Syrian Civil War | Civil war in Afghanistan (1989-1992) | Civil war in Afghanistan (1989–92) |
| Civil war in Afghanistan (1992-1996) | Civil war in Afghanistan (1992–96) | Civil war in Afghanistan (1996-2001) |
| Civil war in Afghanistan (1996–2001) | Civil war in Tajikistan | Civil-military operations |
| Civilian | Civilian control of the military | Civilisées |
| Civilization | Civilization (series) | Civilization V |
| Civilization V: Brave New World | Civilized core | Civitas Popthensis |
| Cizre | CJ Parker (wrestler) | CJCUC |
| CKM matrix | Cl | Claddagh ring |
| Cladding (construction) | Cladistics | Cladium mariscus |
| Cladobranchia | Cladocera | Cladorhynchus |
| Cladorhynchus leucocephalus | Cladosporium | Cladrastis kentukea |
| Claflin, Kansas | Claiborne County, Tennessee | Claiborne Parish, Louisiana |
| Claim rights and liberty rights | Claimed moons of Earth | Clair Cameron Patterson |
| Claire City, South Dakota | Claire Danes | Claire Etcherelli |
| Claire Holt | Claire Lee Chennault | Claire Redfield |
| Clairmarais | Clairton, Pennsylvania | Clam AntiVirus |
| Clam Falls, Wisconsin | Clam Lake Township, Michigan | Clam Union Township, Michigan |
| Clamator | Clamator coromandus | Clamator glandarius |
| Clamator jacobinus | ClamAV | CLAMP |
| ClamWin | ClamWin Antivirus | Clancy Brown |
| Clandestine abuse | Clanga clanga | Clanga pomarina |
| Clangula hyemalis | Clans, Alpes-Maritimes | Clapper bridge |
| Clapperboard | Clara Barton | Clara Basiana |
| Clara Bow | Clara City, Minnesota | Clara Janés |
| Clara Khoury | Clara Zetkin | Clarabelle Cow |
| Clarín (Argentine newspaper) | Clare Boothe Luce | Clare County, Michigan |
| Clare, Iowa | Clare, Michigan | Clare, New York |
| Claremont, Illinois | Claremont, Minnesota | Claremont, New Hampshire |
| Claremont, North Carolina | Claremont, South Dakota | Claremont, Virginia |
| Claremore, Oklahoma | Clarence (2014 TV series) | Clarence Acuña |
| Clarence Day | Clarence Goodson | Clarence King |
| Clarence L. Johnson | Clarence Nash | Clarence Seedorf |
| Clarence Township, Michigan | Clarence Williams III | Clarence, Iowa |
| Clarence, New York | Clarendon Hills, Illinois | Clarendon Township, Michigan |
| Clarendon, Arkansas | Clarendon, New York | Clarendon, Quebec |
| Clarendon, Texas | Clarendon, Vermont | Clarias batrachus |
| Clariden | Clariidae | CLARINASE |
| Clarinda, Iowa | Clarinet | Clarington, Ohio |
| Clarion County, Pennsylvania | Clarion, Iowa | Clarissa, Minnesota |
| Clarithromycin | Clark County, Indiana | Clark County, Wisconsin |
| Clark Duke | Clark Gable | Clark International Airport |
| Clark Johnson | Clark L. Hull | Clark Township, Michigan |
| Clark, South Dakota | Clarkdale, Arizona | Clarke Carlisle |
| Clarke County, Alabama | Clarke's three laws | Clarkedale, Arkansas |
| Clarkesville, Georgia | Clarkfield, Minnesota | Clarkia amoena |
| Clarks Grove, Minnesota | Clarks Hill, Indiana | Clarks, Nebraska |
| Clarksburg, Massachusetts | Clarksburg, Ohio | Clarksburg, Tennessee |
| Clarksburg, West Virginia | Clarksdale, Mississippi | Clarkson, Kentucky |
| Clarkson, New York | Clarkston, Georgia | Clarkston, Michigan |
| Clarkston, Utah | Clarkston, Washington | Clarkstown, New York |
| Clarksville City, Texas | Clarksville, Allegany County, New York | Clarksville, Arkansas |
| Clarksville, Indiana | Clarksville, Iowa | Clarksville, Michigan |
| Clarksville, New Hampshire | Clarksville, Ohio | Clarksville, Tennessee |
| Clarksville, Texas | Clarksville, Virginia | Clarkton, North Carolina |
| Clarno, Wisconsin | Clarques | Clash of Civilizations |
| Clash of Clans | Clash of clans | Clash of Loyalties |
| Clash of the Titans (2010 film) | Clasper | Class (biology) |
| Class (computer programming) | Class conflict | Class consciousness |
| Class discrimination | Class in Marxist theory | Class struggle |
| Classes of computers | Classful network | Classic car |
| Classic metal | Classical antiquity | Classical architecture |
| Classical compound | Classical conditioning | Classical electromagnetism |
| Classical electron radius | Classical element | Classical liberalism |
