- cobblers
 - CDC
 - Comptroller of the Currency
 - Census Bureau
 - Counterterrorist Center
 - CCRC
 - Center for Disease Control and Prevention
 - CTC
 - Casualty Care Research Center
 - certainty
 - chiffonier
 - chest of drawers
 - central office
 - countinghouse
 - carrot family
 - Cornaceae
 - Connaraceae
 - Cunoniaceae
 - cunonia family
 - communist
 - commie
 - collectivist
 - capitalistic
 - conference
 - cooperative
 - Craspedia
 - Conradina
 - Conyza
 - Chiococca
 - Carthamus
 - Carduus
 - Castilleja
 - Clinopodium
 - Culver's physic
 - Cnicus
 - Castilleia
 - Crepis
 - Culvers physic
 - Cichorium
 - Chamaemelum
 - Chelone
 - Chilopsis
 - Chrysothamnus
 - Conoclinium
 - Carlina
 - Collinsia
 - Cestrum
 - Culver's root
 - Cotula
 - Calycophyllum