| OAS |
Offensive
Air Support |
| OAS |
Offensive
Avionics System |
| OB |
Order
of Battle |
| OBEWS |
On-Board
Electronic Warfare Simulator system |
| OBOGS |
On-Board
Oxygen Generating System |
| O-BWO |
"O"
type Backward-Wave Oscillator |
| OCA |
Offensive
Counter Air |
| OCM |
Optical
Countermeasures |
| OCR |
Optical
Character Reader |
| OCR |
Optical
Character Recognition |
| OCR |
Office
of Collateral Responsibility |
| OFC |
Optical
Fibre Cable |
| OHD |
Over-the-Horizon
Detection |
| OL |
Operating
Location |
| OLOGS |
Open
Loop Oxygen Generating System |
| O&M |
Operations
and Maintenance |
| OMEGA |
Ground
based multi-user worldwide VLF navigation system |
| omni |
All,
universally, Omnidirectional radio range |
| OOK |
On-Off
Keying |
| OPCON |
Operational
Control |
| OPlan |
Operations
Plan |
| OpOrd |
Operation
Order |
| OPREP |
Operational
/ Operations Report |
| OPREP |
Operational
event / incident Report |
| OPS |
Operations |
| OPSEC |
Operations
Security |
| OR |
Operational
Readiness |
| ORBAT |
Order
of Battle |
| OSC |
Oscillator |
| OSO |
Offensive
Systems Operator |
| OTA |
Off
The Air |
| OT&E |
Operational
Test and Evaluation |
| OTH |
Over
The Horizon |
| OTH-B |
Over
The Horizon - Backscatter (radar) |
| OTH-F |
Over
The Horizon - Forward scatter |
| OTHT |
Over
The Horizon Targeting |
| OVHT |
Overheat |
| OVLD |
Overload |
Military Acronyms - O