Alphabetical Index of Abbreviations ~ O

Click on the appropriate first letter of the abbreviation that you require

O & M	Operation and maintenance
	Organisation and methods
O alt	Observed altitude
OA	Over all
OAC	Oceanic area control centre
OAS	Offensive air support
OASIS	Onboard automatic data processing support in ships
	Operational analysis of special intelligence systems
OAT	Operational air traffic
	Outside air temperature
OB	Operation budget
	Ore bulk carrier
OBDG	On-board degaussing
OBIGGS	On-board inert gas-generating system
OBM	Orbital ballistic missile
OBOC	Ore/bulk/oil carrier
OBOGS	On-board oxygen-generating system
obst	Obstruction
OC	Officer commanding
OCA	Obstacle clearance altitude
	Oceanic control area
	Offensive, counter-air
	Operational control authority
occ	Occulting
OCH	Obstacle clearance height
OCIMF	Oil Companies´ International Marine Forum
OCL	Obstacle clearance limit
OCOP	Outline contingency operations plan
OCPB	Ocean-capable patrol boat
OCR	Optical character reader
	Optical character recognition
OCU	Operational conversion unit (pilot´s)
ODAS	Oceanographic data acquisition system
ODBC	Open database connectivity
ODBG	On-board degaussing
OECD	Organisation for Economic Co-operation and Development
OEEC	Organisation for European Economic Co-operation
OEM	Original equipment manufacturer
	Own equipment manufacture
OES	Outside electricity supply
OFIS	Operational flight information service
OGC	Office of Government Commerce
OGIS	Open geographic information system
OIC	Officer in charge
OJT	On-the-job training
OLAFAS	On-line automated frequency assignment system
OLDI	On-line data interchange
OM	Outer marker
OMBON	One-man bridge operation
ONC	Operational navigation chart
ONSOD	Omega navigation system operation detail
OOB	Ocean order of battle
OOD	Object-oriented design
OOPC	Ocean Observations Panel for Climate (of UN)
OOTW	Operation other than war
OOW	Officer of the watch
OP	Observation post
OPEC	Organisation of Petroleum Exporting Countries
OPIS	Operational priority indicating system
opO	Operation order
OPR	Office of primary responsibility
OPRC	Oil spill preparedness, response and cooperation
ops	Operations
OPV	Offshore patrol vessel
OR	Operational research
	Other ranks
orbat	Order of battle
ord	Ordnance
ORE	Operational readiness evaluation
ORI	Operational readiness inspection
ORTP	Operational readiness test programme
OS	Ordinary seaman
	Ordnance survey
OSB	Orientated sterling board
OSD	Open shelter deck
OSI	Open systems interconnect (computer)
OSIS	Ocean surveillance information system (satellite)
OSV	Ocean station vessel
OT	Ordinary tide
OTAR	Overseas tariffs and regulations
OTEC	Ocean thermal energy conversion
OTHR	Over-the-horizon radar
OTHT	Over-the-horizon targeting
OTS	Operations and training support
OTSF	Operations and training support flight
OTSR	Optimum track ship routing
OTU	Operational training unit
OWS	Ocean weather ship
oz	Ounce (28.35 g)