| Abbreviation | Definition |
|---|---|
| ISRT | Information, Surveillance, Reconnaissance and Targeting |
| ISS | Information Systems Security |
| ISS | Injury Severity Score |
| ISS | Inspection Selection System |
| ISS | In-System Select |
| ISS | Integrated Systems Support |
| ISS | Interactive Survivability Simulation |
| ISS(s) | injury severity score(s) |
| ISSA | Inter-Service Support Agreement |
| ISSB | Inter Services Selection Board |
| ISSC | Information Systems Software Center |
| ISSG | Intelligence Senior Steering Group |
| ISSL | Immediate Skill Shortage List |
| ISSL | Initial Spares Support List |
| ISSM | Information System Security Manager |
| ISSO | Information Systems Security Officer |
| ISSR | Incremental Software Specification Review |
| ISSSB | Information Systems Software Support Bulletin |
| IST | individual strength test |
| IST | In-Service Testing |