| Abbreviation | Definition |
|---|---|
| JCMPO | Joint Cruise Missile Project Office |
| JCMWG | Joint Civil Military Working Group |
| JCN | Joint Communications Network |
| JCN | Joint Cooperative Network |
| JCO | Jewish Combat Organization |
| JCO | Junior Commissioned Officer (Indian rank) |
| JCOE | Joint Common Operating Environment |
| JCOT | Joint Collection Observation Team |
| JCP | U.S./Canada Joint Certification Program |
| JCRP | Joint Command Readiness Program |
| JCS | Joint C4ISR System |
| JCS | Joint Chiefs of Staff |
| JCS | Joint Combat System |
| JCS | Joint Communications Support |
| JCS | Jumper Candidate School |
| JCSA | Joint C4ISR System Architecture |
| JCS-ACA | Joint Chiefs of Staff Automatic Conference Arranger |
| JCSAN | Joint Chiefs of Staff Alerting Network |
| JCSAR | Joint Combat Search and Rescue |
| JCSB | Joint Contracting Support Board |