- Cobalt bomb
- Cobble
- Cobbler
- Cobol
- Cobra
- Cocaine
- Cock
- Codex
- Codger
- Coed
- Coefficient
- Coessential
- Coffee break
- Coffee plant
- Coffer
- Cogitate
- Cogitation
- Cogitative
- Cognate
- Cognisance
- Collective noun
- College
- Collegian
- Colliding
- Collision
- Collision course
- Collusiveness
- Collyrium
- Colocasia
- Comb
- Combative
- Combing
- Come
- Come across
- Come and go
- Come at
- Come to the surface
- Come together
- Come under
- Comely
- Comemorated
- Comet
- Comfort station
- Comical
- Comilona
- Common sense
- Communalism
- Communicable
- Communication
- Communication satellite
- Comorbid
- Compliment
- Components
- Comport with
- Composes
- Composing
- Compositions
- Compound interest
- Compound wall
- Compoundable offence
- Conceited
- Conceive
- Conceived
- Concentrate
- Concentrically
- Concerned
- Concerned about
- Concerted
- Concertina
- Conciliate
- Confabulate
- Confederate
- Confessant
- Confessional
- Confined at the surface
- Confinement
- Confirm
- Confiscating
- Congressional
- Congressman
- Congruity
- Conically
- Conics
- Conjectural
- Conjecture
- Conjunction of planets
- Conjure
- Conjurer
- Conk
- Connect time
- Conservation
- Conservation biology
- Conservator
- Conservatory
- Considerate
- Consist
- Consistency, consistence
- Consoles
- Consolidate
- Contemplative