Check all full forms of O here

CODE	ABBREVIATION
O	Organization
O/S	Operating System
O:)	Angel(ic) / Halo
O:-)	Angel(ic) / Halo
O:O	A girl is mooning you
O--<	Fishy
O2	Object Oriented
OA	Office Automation / Order Administration / Order Administration
OA&M	Operations Administration & Maintainance
OAG	Open Applications Group
OAGEE	Official Airlines Guide Electronic Edition
OAM	Operations Administration and Maintenance
OAM&P	Operation Administration Maintenance and Provisioni
OAO	Over And Out
OARS	On a Related Subject
OASYS	Office Automation SYStem
OATUS	On a Totally Unrelated Subject
OAUS	on an unrelated subject
Ob-	[as a prefix] obligatory
Ob	Ob- [as a prefix] obligatory / Out of Bounds
OBE	Overtaken By Events
Objoke	Obligatory joke
OBTW	Oh by the way
OBU	Option Business Unit
OC	Operator Centralization
OCAP	Orange Cats Are Pretty
OCC	Other Common Carrier
OCD	Out of Cell Delineation
OCE	Open Collaboration Environment / Other Common carrier channel Equipment / Other Common Equipment
OCF	Object Components Framework
OCIRYITM	Of course i'll respect you in the morning
OCIS	Organized Crime Information Systems
OCLC	Online Computer Library Catalog
OCPS	Open Content Publisher Standard
OCR	Optical Character Reader / Optical Character Recognition
OCRC	Option Change Review Committee
OCS	Original ChipSet the first custom chipset for the amiga.
OCU	Office Channel Unit
OCX	OLE Custom control
OD	Outdial
ODA	Office Document Architecture
ODAC	Operations Distribution Administration Center
ODBC	Open Database Compliant/Connectivity
ODD	Operator Distance Dialing
ODDD	Operator Direct Distance Dialing
ODI	Open Data Interface / Open Data-link Interface
ODMA	Open Document Management API
ODMG	Object Database Management Group
ODN	OutDial Notification
ODS	Optical Data Systems/Stream
ODSI	Open Directory Service Interface
OEM	Original Equipment Manufacturer
OEMF	Open Element Management Framework
OF	Overflow
OFB	(K-bit) Output Feedback
OFC	Open Financial Connectivity (specification)
OFDM	Orthogonal Frequency Division Multiplexing
OFG	Originally Funny Guys
OFNPS	Outstate Facility Network Planning System
OGT	OutGoing Trunk
OGT	Out-Going Trunk
OGVT	OutGoing Verification Trunk
OH	(modem) Off Hook
OHP	OverHead Projection (film)
OIC	Oh I See
OIC	Oh I see
OIC	Oh I See
OIC	Oh I See!
OIP	Opportunity Investment Planning
OIS	Office and Information Systems
OJT	On the Job Training
OL	Old Lady (significant other)
OL	Ordered List
OLAP	OnLine Analytical Processing
OLAP	On-Line Analytical Processing
OLE	Object Linking and Embedding
OLI	Originating Line Information
OLTM	Optical Line Terminating Multiplexer
O-LTM	Optical Line Terminating Multiplexer
OLTP	OnLine Transaction Processing
OLTP	On-Line Transaction Processing
OLX	Off-Line eXpress
OM	Old Man (significant other)
OMA	Object Management Architecture
OMC	Office of Munitions Control
OMG	Oh My God / Object Management Group (model)
OML	Open Modeling Language
OMM	Output Message Manual
OMNI	Organising Medical Networked Information
OMPF	Operation and Maintenance Processor Frame
OMR	Optical Mark Recognition
OMT	Object Modeling Technique
ONAC	Operations Network Administration Center
ONAL	Off Network Access Line
ONAW	Oh No! Another Wedgie
ONE	Open Network Environment
ONI	Operator Number Identification
ONLY	Used by shareware authors who over-price ie. "$99.95."
ONMS	Open Network Management System
ONNA	Oh No Not Again
ONNTA	Oh No Not This Again
ONU	Optical Networking Unit
OO	Object Orientation/Oriented
OOB	Out Of Band(width)
OOC	Out Of Character
OOD	Office of Development (Central Engineering)
OODBMS	Object-Oriented DataBase Management System
OODCE	Object Oriented Distributed Computing Environment
OOF	Out Of Frame
OOFNet	Our Own Fucking Net
OOI	Out Of Interest
OOO	Out Of Order
OOP	Object Oriented Programming
OOPSLA	Object Oriented Programming Systems Language and Appl
OOSOOM	Out of Sight Out of Mind
OOT	Object Oriented Technology
OOTB	Out Of The Box (brand new)
OOTC	Obligatory On-Topic Comment
OOUI	Object Oriented User Interface
OP	Operator / Option / Outside Plant
OPAC	On-line Public Access Catalogue
OPAL	On-line Presentation Access Library
OPC	Organic Photoconducting Cartridge / Originating Point Codes
OPCR	Operator Actions Program / Original Program Clock Reference
OPEN	Protocol Enhanced Networks
OPEOS	Outside Plant Engineering and Operations System
OPI	Open Prepress Interface
OPL	Organizer Programming Language
OPM	Outage Performance Monitoring / Outside Plant Module
OPOM	Organizational Program Office Manager
OPOS	OLE for Point Of Sale
OPS	Off Premises Station
OPS	Operations / Oracle Parallel Server
OPSM	Outside Plant Subscriber Module
OPT	Open Protocol Technology
OPX	Off Premises eXtension
OQR	Object Query Language
OQS	Object Query Service
OR	Originating Register
ORB	Object Request Broker / Office Repeater Bay
ORDBMS	Object-Relational DataBase Management System
ORG	Organization (usually as .org)
ORM	Object Role Modeling / Optical Remote Module
ORMS	Operating Resource Management System
ORPC	Object Remote Procedure Call
ORSD	Object Registration Service Daemon (usually as orsd)
OS	Operating System / Operator Service / Output Spy (ITS) / OutState
OS/2	Half an Operating System / Obsolete Soon Too. / Operating System/2
O-S-<	In a hurry
OSAC	Operator Services Assistance Center
OSC	Operator Services Center / OSCillator
OSCA	Open Systems Color Association
OSD	Open Software Description
OSDS	Operating System for Distributed Switching
OSE	Open Systems Environment / Open Software Foundation / Operations System Function
OSF/DCE	Open Software Foundation Distributed Computing Environ
OSI	Open Systems Interconnect(ion) / Open Standards Interconnect(ion) /
OSID	Originating Signaling Identifier
OSIE	Open Systems Interconnection Environment
OSINET	Open Systems Interconnection NETwork
OSIRM	Open Systems Interconnection Reference Model
OSM	OS Specific Module
OSME	Open Systems Message Exchange
OSO	Originating Signaling Office
OSP	Office of Sales Programs / OutSide Plant
OSPF	Open Shortest Path First (protocol)
OSPS	Operator Service Position System
OSR	OEM Service Release / OEM System Release / Operating System-Specific / Operational Support System/Services / Operator Service(s) System
OSSWG	Office System Standards Work Group
OST	Originating Station Treatment
OSTA	Optical Storage Technology Association
OSTC	Open Systems Testing Consortium
OSTP	Office of Science and Technology Policy
OSWS	Operating System WorkStation
OT	Off topic / Open Transport
OTA	Office of Technology Assessment
OTB	Off to bed
OTC	Over the Counter / Operating Telephone Company
OTD	Off the Dock
OTDR	Optical Time Domain Reflectometer(s)
OTE	Off Track Excursion / Off Track Experience
OTF	On the Floor / Object Testing Framework
OTFM	Only the Facts Mam
OTL	Out To Lunch / OSI Testing Liaison
OTM	Object Transaction Monitor
OTOH	On The Other Hand
OTOOH	On The Other Other Hand
OTP	One Time Programmable / Order Transaction Processing
OTQ	Out-going Trunk Queuing
OTR	Operational Trouble Report
OTS	Off The Shelf
OTT	Over The Top
OTTH	On the third hand
OTTOMH	Off the Top of My Head
OTTOMHAROOB	Off the Top of My Head and Rolling Out of Bounds
OTW	On the Whole
OU	Organizational Unit
OUI	Organization Unique Identifier / Organizational Unit I
OURS	Open User Recommended Solutions (user group)
OUTWATS	OUTward Wide Area Telecommunications Service
OV	OpenView
OVD	Optical Video Disk
OVDA	Optical Video Disc Association
OW	Over-Write
OWF	One-Way Function / Optimum Working Frequency
OWL	Object Windows Library
OWRTS	Open - Wire Radio Transmission System
OWTL	Open - Wire Transmission Line
OWTTE	Or Words to that Effect
O-Z-<	In a big hurry

O

OAPNA           :- Organization of Asia and Pacific News Agency

OAU                :- Organization of African Unity

OCS                :- Overseas Communication Service

OECD             :- Organization for Economic Cooperation and Development

OEEC              :- Organization for European Economic Cooperation

OGL                :- Open General License

OIL                 :- Oil India Limited

OK                  :- All Correct

OIGS              :- On India Government Service

ONGC            :- Oil and Natural Gas Commission

OMSS            :- Open Market Sale Scheme

OPEC              :- Organization of Petroleum Exporting Countries

OPPI                :- Organization of Pharmaceutical Producers of India

OSCE              :- Organization of European Security Council