ORCHID: Optical Radiation Cooling and Heating in Integrated Devices
ORCON: Originator Controlled
ORD: Operational Requirements Document
ORD: Operational Requirements Documents
ORD: Operationally Ready Date
Ord: Ordnance
ORE: Operational Readiness Exercise
ORF: Official Representation Fund
org: Organization
ORI: Operational Readiness Inspection
ORISE: Oak Ridge Institute for Science and Education
ORNL: Oak Ridge National Laboratory
ORO: Oak Ridge Operations
ORR: Oak Ridge Reservation
ORS: Octahedral Research Satellite
ORS: Offensive Radar Set
ORS: Operational Research Section
ORs: Other Ranks
ORTU: Operational & Refresher Training Unit
OS: Observers School
OS: operating system
OS-21: Observing System 21st Century
OSA: Open Systems Architecture
OSAP: Ocean Surveillance Assessment Program
OSAS: Operational Space Application System
OSB: One Shot Battery
OSC: Office of the Security Council
OSC: Officers Senior Course officers
OSC: On-Scene Commander
OSC: Operational Support Company
OSC: Operations Support Center
OSC: Overseas Staff College
OSCA: Office of Security Cooperation Afghanistan
OSCAR: Optical Submarine Communications by Aerospace Relay
OSCARCP: Operations Support Center and Rear Command Post
OSCE: Organization for Security and Cooperation in Europe
OSD: Office of the Secretary Defense
OSD: Office of the Secretary of Defense
OSDPD: Office of Satellite Data Processing and Distribution
OSDPE: Office of the Secretary of Defense Program Element