citrus - cognitive
- clutter
- clutter traffic
- Clyde
- Clydesdale
- clyster
- clyster pipe
- CM
- cm. centimetre
- CMD Centralized Message Distribution
- CMEA Council for Mutual Economic Aid
- cmm cubic millimetre
- CMOS complementary metal-oxide semiconductor
- cmps centimetre per second
- CMY cyan-magenta-yellow
- CMYK cyan-magenta-yellow-black
- CN/A Customer Name / Address
- CNN Cable News Network
- CNO Chief of Naval Operations
- CNR Canadian National Railways
- CO