CSU
- Airline codes-C
- Cagayan State University
- California State University
- Caraga State University
- Cardinal Stritch University
- Central Sanskrit University
- Central South University
- Central State University
- Channel service unit
- Charles Sturt University
- Charleston Southern University
- Chelyabinsk State University
- Cheng Shiu University
- Chicago State University
- Christian Social Union (UK)
- Christian Social Union in Bavaria
- Chronic spontaneous urticaria
- Civil Service Union
- Clayton State University
- Cleveland State University
- Colorado State University
- Columbia Southern University
- Columbus State University
- Concordia Student Union
- Connecticut State University System
- Constant speed unit
- Coppin State University
- Czech Statistical Office
- Forensic science