| Abbreviation | Definition |
|---|---|
| CTF | Counter Terrorist Force |
| CTIIC | Cyber Threat Intelligence Integration Center |
| CTM | Complaint Tracking Module |
| CTO | Commercial Travel Office |
| CTO | Contribution Towards Overheads |
| CTP | Call To Power |
| CTRC | Colorado Technical Reference Center |
| CTS | Canada Treaty Series |
| CTSA | Clinical and Translational Science Award (grants) |
| CTSO | Coordinating Tax Services Office |
| CTT | Constructive Travel Time |
| CTTSO | Combating Terrorism Technical Support Office |
| CTU | Counter Terrorist Union |
| CTU | Counter Terrorist Unit |
| CU | Classification Unit |
| CUAP | College and University Affiliations Program |
| CUES | a Code for Unplanned Encounters at Sea |
| CUPID | Computer Usage And Personal Identification Database |
| CURE | Constitutionally Unified Republic For Everyone |
| CUSEC | Central U.S. Earthquake Consortium |