O/SOperating System
O:)Angel(ic) / Halo
O:-)Angel(ic) / Halo
O:OA girl is mooning you
O2Object Oriented
OAOffice Automation / Order Administration / Order Administration
OA&MOperations Administration & Maintainance
OAGOpen Applications Group
OAGEEOfficial Airlines Guide Electronic Edition
OAMOperations Administration and Maintenance
OAM&POperation Administration Maintenance and Provisioni
OAOOver And Out
OARSOn a Related Subject
OASYSOffice Automation SYStem
OATUSOn a Totally Unrelated Subject
OAUSon an unrelated subject
Ob-[as a prefix] obligatory
ObOb- [as a prefix] obligatory / Out of Bounds
OBEOvertaken By Events
ObjokeObligatory joke
OBTWOh by the way
OBUOption Business Unit
OCOperator Centralization
OCAPOrange Cats Are Pretty
OCCOther Common Carrier
OCDOut of Cell Delineation
OCEOpen Collaboration Environment / Other Common carrier channel Equipment / Other Common Equipment
OCFObject Components Framework
OCIRYITMOf course i'll respect you in the morning
OCISOrganized Crime Information Systems
OCLCOnline Computer Library Catalog
OCPSOpen Content Publisher Standard
OCROptical Character Reader / Optical Character Recognition
OCRCOption Change Review Committee
OCSOriginal ChipSet the first custom chipset for the amiga.
OCUOffice Channel Unit
OCXOLE Custom control
ODAOffice Document Architecture
ODACOperations Distribution Administration Center
ODBCOpen Database Compliant/Connectivity
ODDOperator Distance Dialing
ODDDOperator Direct Distance Dialing
ODIOpen Data Interface / Open Data-link Interface
ODMAOpen Document Management API
ODMGObject Database Management Group
ODNOutDial Notification
ODSOptical Data Systems/Stream
ODSIOpen Directory Service Interface
OEMOriginal Equipment Manufacturer
OEMFOpen Element Management Framework
OFB(K-bit) Output Feedback
OFCOpen Financial Connectivity (specification)
OFDMOrthogonal Frequency Division Multiplexing
OFGOriginally Funny Guys
OFNPSOutstate Facility Network Planning System
OGTOutGoing Trunk
OGTOut-Going Trunk
OGVTOutGoing Verification Trunk
OH(modem) Off Hook
OHPOverHead Projection (film)
OICOh I see
OICOh I See!
OIPOpportunity Investment Planning
OISOffice and Information Systems
OJTOn the Job Training
OLOld Lady (significant other)
OLOrdered List
OLAPOnLine Analytical Processing
OLAPOn-Line Analytical Processing
OLEObject Linking and Embedding
OLIOriginating Line Information
OLTMOptical Line Terminating Multiplexer
O-LTMOptical Line Terminating Multiplexer
OLTPOnLine Transaction Processing
OLTPOn-Line Transaction Processing
OLXOff-Line eXpress
OMOld Man (significant other)
OMAObject Management Architecture
OMCOffice of Munitions Control
OMGOh My God / Object Management Group (model)
OMLOpen Modeling Language
OMMOutput Message Manual
OMNIOrganising Medical Networked Information
OMPFOperation and Maintenance Processor Frame
OMROptical Mark Recognition
OMTObject Modeling Technique
ONACOperations Network Administration Center
ONALOff Network Access Line
ONAWOh No! Another Wedgie
ONEOpen Network Environment
ONIOperator Number Identification
ONLYUsed by shareware authors who over-price ie. "$99.95."
ONMSOpen Network Management System
ONNAOh No Not Again
ONNTAOh No Not This Again
ONUOptical Networking Unit
OOObject Orientation/Oriented
OOBOut Of Band(width)
OOCOut Of Character
OODOffice of Development (Central Engineering)
OODBMSObject-Oriented DataBase Management System
OODCEObject Oriented Distributed Computing Environment
OOFOut Of Frame
OOFNetOur Own Fucking Net
OOIOut Of Interest
OOOOut Of Order
OOPObject Oriented Programming
OOPSLAObject Oriented Programming Systems Language and Appl
OOSOOMOut of Sight Out of Mind
OOTObject Oriented Technology
OOTBOut Of The Box (brand new)
OOTCObligatory On-Topic Comment
OOUIObject Oriented User Interface
OPOperator / Option / Outside Plant
OPACOn-line Public Access Catalogue
OPALOn-line Presentation Access Library
OPCOrganic Photoconducting Cartridge / Originating Point Codes
OPCROperator Actions Program / Original Program Clock Reference
OPENProtocol Enhanced Networks
OPEOSOutside Plant Engineering and Operations System
OPIOpen Prepress Interface
OPLOrganizer Programming Language
OPMOutage Performance Monitoring / Outside Plant Module
OPOMOrganizational Program Office Manager
OPOSOLE for Point Of Sale
OPSOff Premises Station
OPSOperations / Oracle Parallel Server
OPSMOutside Plant Subscriber Module
OPTOpen Protocol Technology
OPXOff Premises eXtension
OQRObject Query Language
OQSObject Query Service
OROriginating Register
ORBObject Request Broker / Office Repeater Bay
ORDBMSObject-Relational DataBase Management System
ORGOrganization (usually as .org)
ORMObject Role Modeling / Optical Remote Module
ORMSOperating Resource Management System
ORPCObject Remote Procedure Call
ORSDObject Registration Service Daemon (usually as orsd)
OSOperating System / Operator Service / Output Spy (ITS) / OutState
OS/2Half an Operating System / Obsolete Soon Too. / Operating System/2
O-S-<In a hurry
OSACOperator Services Assistance Center
OSCOperator Services Center / OSCillator
OSCAOpen Systems Color Association
OSDOpen Software Description
OSDSOperating System for Distributed Switching
OSEOpen Systems Environment / Open Software Foundation / Operations System Function
OSF/DCEOpen Software Foundation Distributed Computing Environ
OSIOpen Systems Interconnect(ion) / Open Standards Interconnect(ion) /
OSIDOriginating Signaling Identifier
OSIEOpen Systems Interconnection Environment
OSINETOpen Systems Interconnection NETwork
OSIRMOpen Systems Interconnection Reference Model
OSMOS Specific Module
OSMEOpen Systems Message Exchange
OSOOriginating Signaling Office
OSPOffice of Sales Programs / OutSide Plant
OSPFOpen Shortest Path First (protocol)
OSPSOperator Service Position System
OSROEM Service Release / OEM System Release / Operating System-Specific / Operational Support System/Services / Operator Service(s) System
OSSWGOffice System Standards Work Group
OSTOriginating Station Treatment
OSTAOptical Storage Technology Association
OSTCOpen Systems Testing Consortium
OSTPOffice of Science and Technology Policy
OSWSOperating System WorkStation
OTOff topic / Open Transport
OTAOffice of Technology Assessment
OTBOff to bed
OTCOver the Counter / Operating Telephone Company
OTDOff the Dock
OTDROptical Time Domain Reflectometer(s)
OTEOff Track Excursion / Off Track Experience
OTFOn the Floor / Object Testing Framework
OTFMOnly the Facts Mam
OTLOut To Lunch / OSI Testing Liaison
OTMObject Transaction Monitor
OTOHOn The Other Hand
OTOOHOn The Other Other Hand
OTPOne Time Programmable / Order Transaction Processing
OTQOut-going Trunk Queuing
OTROperational Trouble Report
OTSOff The Shelf
OTTOver The Top
OTTHOn the third hand
OTTOMHOff the Top of My Head
OTTOMHAROOBOff the Top of My Head and Rolling Out of Bounds
OTWOn the Whole
OUOrganizational Unit
OUIOrganization Unique Identifier / Organizational Unit I
OURSOpen User Recommended Solutions (user group)
OUTWATSOUTward Wide Area Telecommunications Service
OVDOptical Video Disk
OVDAOptical Video Disc Association
OWFOne-Way Function / Optimum Working Frequency
OWLObject Windows Library
OWRTSOpen - Wire Radio Transmission System
OWTLOpen - Wire Transmission Line
OWTTEOr Words to that Effect
O-Z-<In a big hurry


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