- chopper
- chord
- chording
- chromodynamics
- circuit
- circuitry
- circular coil
- circular fin
- chorded coil
- chromel
- chromosphere
- circuit board
- circuit design
- circuit testing
- circular accelerator
- circular flow
- circular magnetostriction
- circulated refrigerant
- circulation receiver
- circulator
- cladding
- circulation circuit
- circulation ratio
- circumpolar star
- circumsphere
- clamping die
- Clausius cycle
- Clausius number
- clearance
- clearance vapour
- cleat
- cleavage
- climatic chamber
- climatic engineering
- clarification
- classical chaos
- Clausius" statement
- clean line
- clearance gauge
- clearance pocket
- clearance space
- clearing
- clearing signal
- climatic system
- climatic variation
- clip connection
- clipping
- clock motor
- clock-dial
- clothoid
- cloud chamber
- cloud telemeter
- cloudiness
- cluster decay
- clustered
- clustering
- co-ordination
- co-tree
- CO2 condenser
- CO2 indicator
- CO2 snow
- coacting
- coactivation
- coagulability
- coagulable
- coagulum
- coarse control
- coarse filter
- coarse-crystalline
- coast station
- coastal refraction
- coaxial capacitor
- coaxial hybrid
- coaxial isolator
- coaxial switch
- clip lead
- clock
- clock generator
- clock rate
- close coupling
- close packing
- closed cavity
- closed chiller
- closed cooler
- closed cycle
- closed domain
- closed string
- closing pressure
- closing time
- code conversion
- code division
- codec
- coded
- coder
- codimension
- coercitive
- cog
- coherence
- coherence length
- coherer