O: Oblique
O: Oscar
O: Oscar Time Zone
O&C: Operations & Control
O&I: Operations & Intelligence
O&M: Operate and Maintain
O&M: Operation and Maintenance
O&M: Operations and Maintenance
O&S: Operations & Support
O&S: Operations and Support

O/A: On or About
O/O: Order of Operations
OA: Office Automation
OA: Operational Area
OA: Operations Analysis
OAC: Objective Architecture Center
OAD: Objective Architecture Document
OAD: operational availability date
OAD-2: Objective Architecture Document, 2nd Iteration
OADF: Overseas Aircraft Delivery Flight
OADR: Originating Agency Determination Required
OADU: Overseas Aircraft Delivery Unit
OAF: Operation Allied Force
OAFS: Onazuka Air Force Station
OALAN: Office Automation Local Area Network
OAMP: Optical Airborne Measurements Program
OANS: Observers Air Navigation School

OAP: Offset Aim Point
OAP: Organizational Assessment Package
OAPEC: Organization of Arab Petroleum-Exporting Countries
OAPU: Overseas Aircraft Preparation Unit
OAR: Obusna Aeroplansva Radionica
OAS: Offensive Air Support
OAS: Offensive Avionics System
OAS: Onizuka Air Station
OAS: Open Architecture System
OAS: Organization of American States
OASA: Office of the Assistant Secretary of the Army
OASD: Office of the ASD

OASD: Office of the Assistant Secretary of Defense