- cosmic ray
- cosmogony
- cosmos
- cost curve
- cost function
- cost table
- cotangent curve
- countability
- countable
- countable compact
- counter capacity
- counter circuit
- counter hand
- counter-controller
- countermeasure
- country name
- country-specific
- coupled transistors
- coupling
- coupling capacitor
- courseware
- courtesy of
- covariance tool
- covariant curve
- covariant derivative
- covariant functor
- covariant index
- covariant tensor
- covariant vector
- cover
- cover material
- coverage area
- covering domain
- covering homotopy
- covering manifold
- covering operation
- covering transformation
- cowl
- CP command
- CPU cycle
- CPU time
- crack stress
- cracker
- cracker condition
- crawl
- creation
- creation operator
- creative
- creative set
- creativity software
- CP privilege
- CP read
- CPU timer
- CPU-bound
- cracking tar
- crane
- crash
- create
- creation date
- creation support
- creation-time
- creator
- credible
- creep settlement
- creep test
- crescent
- crescent-shaped
- crest
- crest element
- crime
- crisis
- crisis-cross
- criss-cross
- criteria
- criterion
- critical band
- critical graph
- critical resource
- criticalsection
- crop
- crop mark
- cross assembly
- crunch
- crush zone
- cryotron computer
- cryptochannel
- cryptographic communication
- cryptographic security
- cryptographic system
- crystallographic group
- crop marks
- cross assembler
- cross bond
- cross compiler
- cross connecting
- cross hairs
- cross perforation
- cross product
- cross-border
- cross-connect