| Abbreviation | Definition |
|---|---|
| COS | Critical Occupational Specialty |
| COS | Critical Operational Specialties |
| COSAGE | Combat Sample Generator |
| COSATI | Committee for Scientific and Technical Information, Washington, DC |
| COSATI | ommittee for Scientific and Technical Information, Washington, DC |
| COSC | Chiefs Of Staff Committee |
| COSC | Combat and Operational Stress Control |
| COSC | Combat Operational Stress Control |
| COSC | Combat Operational Stress Control (USMC) |
| COSCOM | Corps Support Command |
| COSE | Common Open Software Environment |
| COSG | Cuba Organic Support Group |
| COSIN | Control Staff Instructions |
| COSIS | Care Of Supplies In Storage |
| COSMIC | NATO (North Atlantic Treaty Organization) Security Classification Category |
| COSMOS | Counter Surge Mission Mortar System |
| COSPAS | COsmicheskaya Sistyema Poiska Avariynch Sudov (Space System for Search of Distressed Vessels (Russian Satellite System)) |
| COSR | Combat and Operational Stress Reactions |
| COSS | Commander's OPSEC Support System |
| COT | Commanding Officer of Troops |