| Acronym | Meaning |
| APDS | Armour-Piercing |
| AOU | American Ornithologists' Union |
| PLW | Palau (ISO 3166 Trigram) |
| ALERT | Advanced Linked Extended Reconnaissance And Targeting - Attack And Launch Early Reporting To Theatre |
| HEER | High-Explosive Extended Range (ammunition) |
| KHR | Cambodian Riel (ISO 4217 Currency Code) |
| JRA | Japanese Red Army - Joint Rear Area |
| OPSEC | Operations Security - Open Platform For Security |
| DTIC | (U.S.) Defense Technical Information Center |
| O | Oberst - Observer - Obstacle - Octal - Officer - Official - Oh - Operational - Operator - Oprah (magazine) - Outstanding -Oxygen |