Letter O: Data Formats & File Extensions

Search for data file formats and extensions that begin with the letter O, or search more than 4,000 file extensions by the letter or number the file format starts with.

With literally thousands of data file formats employed by Windows and Window-based apps, keeping track of all the file extensions employed by your software applications and programs can be quite a challenge. Fortunately, Webopedia’s Complete List of Data File Formats and File Extensions makes it quick and easy to sift through thousands of file extensions and data file formats to find exactly what you need. You can peruse the full list or search for data formats and file extensions based on the letter they start with from the table below.

Number Symbol A B C D E F G H I J K
L M N O P Q R S T U V W X Y Z Full List

Data File Formats that Begin with the Letter ‘O’

.o Object file (unix – Atari – GCC)
.o$$ Outfile (Sprint)
.oaz Fax (NetFax Manager)
.ob Object cut/paste file (IBM LinkWay)
.obd MS Office Binder
.obj Object code (Intel Recolatable Object Module)
.obr Object browser data file (Borland C++)
.obs Script (ObjectScript)
.obv Visual interface (ObjectScript)
.oca Control Typelib Cache
.ocf Object Craft File (Object Craft)
.ocm AOL Advertising Control files
Internet Odyssey 2 Update
.ocp Advanced Art Studio
Offline Commander Project file
.ocr Incoming fax transcribed to text (FAXGrapper)
.oct Radiance Octree Format
.ocx OLE ActiveX custom control
.odf Open Document Interchange
BattleZone Cartographers Guild file
Star Trek Armada Ship/Structure Infomation
.odg OpenDocument Graphic file
.odl Type library source (Visual C++)
.odp OpenOffice Presentation file
.ods OpenOffice Spreadsheet file
.odt OpenOffice OpenDocument text document
.oeb Outlook Express Backup Wizard
.oem TextSetup OEM file
.ofc Open Financial Connectivity file
.ofd Form definition (ObjectView)
.off Object File Format vector graphics
.ofm Adobe font
.oft MS Outlook Item Template
.ofx Olicom Fax
Open Financial Exchange file
.ogg Ogg Vorbis Codec Compressed WAV file
.ogm Ogg Vorbis Compressed Video file
.ogv Video Container file
.okt Music (Oktalizer)
.olb Object library (VAX)
.old Backup file
.ole Object Linking and Embedding Object
.oli Text file (Olivetti)
.oma OpenMG Music file
.omf Open Media file
.omg OpenMG Jukebox
.oms Briggs Softworks Order Maven
Macintosh MP3 Music Format
Omega Downloader Configuration file
.ond Lotus Notes-related file
.one OneNote Document File
.ont Bible file
.oom Swap file (Shroom)
.opd Omnipage file
.opf Flip Album file
Open Packaging Format file
.opl Psion Organiser Programming Language Source file
.opn Active options (Exact)
.ops Microsoft Office profile settings file
.opt Optimize support file (QEMM)
.opw Organization chart (Org Plus for Windows)
.opx Inactive options (Exact)
.or2 Lotus Organizer 2 file
.or3 Lotus Organizer 97 file
.or4 Lotus Organizer file
.or5 Lotus Organizer file
.ora Parameter file (Oracle)
.org Calendar file (Lotus Organizer)
.osd Open Software Description file
.oss MS Office Saved Search
.ost Microsoft Outlook Offline file
.otf Open Type Format
.otl Outline font description (Z-Soft Type Foundry)
.otx Text file (Olivetti Olitext Plus)
.out Output file
.ov1 Overlay file (part of program to be loaded when needed)
.ov2 Overlay file (part of program to be loaded when needed)
.ovd Datafile (ObjectVision)
.ovl Overlay file (part of program to be loaded when needed)
.ovr Overlay file (part of program to be loaded when needed)
.ovw Cool Edit Pro Overviewfile
Cubase .WAV File Image
DIANA Overview file
.ows Web Studio 2 Project file
.oxt Open Office Extension file

Recommended Reading: An Introduction to Data File Formats and Their File Extensions

Number Symbol A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Full List

This article was last updated on April 12, 2012

Top Articles

Huge List Of Texting and Online Chat Abbreviations

From A3 to ZZZ we list 1,559 text message and online chat abbreviations to help you translate and understand today's texting lingo. Includes Top...

How To Create A Desktop Shortcut To A Website

This Webopedia guide will show you how to create a desktop shortcut to a website using Firefox, Chrome or Internet Explorer (IE). Creating a desktop...

The History Of Windows Operating Systems

Microsoft Windows is a family of operating systems. We look at the history of Microsoft's Windows operating systems (Windows OS) from 1985 to present...

Hotmail [Outlook] Email Accounts

  By Vangie Beal Hotmail is one of the first public webmail services that can be accessed from any web browser. Prior to Hotmail and its...

Graphics File Formats

Graphics file formats are not created equal. Knowing which one to use and...

10 Fun Facts To...

The following mobile phone facts and statistics deliver an update on the status...

10 Interesting Facts About...

The following Cybersecurity facts provide a brief introduction, enabling students, developers, and organizations...