- Cold-blooded
- Cold-hearted
- Coleslaw
- Coliform
- Coliseum
- Colitis
- Collaboratively
- Collage
- Collapse
- Collapsible
- Collar beam
- Collectedly
- Colon
- Colonial
- Colonialism
- Colonization
- Colonize
- Colophon
- Colophony
- Colorectal
- Colour bar
- Colour printing
- Colouring
- Colt
- Come to the surface
- Come together
- Come under
- Comely
- Comemorated
- Comet
- Comfort station
- Comical
- Comilona
- Common sense
- Communalism
- Communicable
- Communication
- Communication satellite
- Comorbid
- Compiling
- Complacence
- Complete eradication
- Complete figure
- Completed
- Completeness
- Completion
- Complex
- Complexion
- Complexity
- Compliance
- Compliant
- Compressed air
- Comprising
- Compunction
- Compute
- Computer graphics
- Comrade
- Comsat
- Con man
- Concatenate
- Concatenation
- Concede
- Condensation of franctions into divisible factors
- Condensed milk
- Condenser
- Condescending
- Condiment
- Condiments
- Condition
- Conditional
- Conditional probability
- Condo lent
- Condominium
- Conduct
- Cone off
- Confiscator
- Conflagration
- Conflict
- Conflicting
- Confluent
- Conform to
- Confound
- Confront
- Confronting
- Confuse with
- cryptocurrency
- Congenital heart defects
- Congeries
- Congest
- Conglomerate
- Conglomeration
- Conglutinate
- Conservation
- Conservation biology
- Conservator
- Conservatory
- Considerate
- Consist
- Consistency, consistence
- Consoles