Here is some File EXTENSION Details..
A Object code library
A Library file (Unix)
AA Audible audio file (commonly used for downloadable audio books)
AAM Authorware shocked file
AAS Authorware shocked packet
AB Applix Builder file
ABF Adobe Binary Screen Font
ABK Backup file (PrintMaster Gold)
ABK Corel Draw AutoBackup
ABM Audio album file (HitPlayer)
ABO Applix Builder Turbo file
ABS MPEG Audio Sound file
ABS Standard GNU compiler output file for a PC platform
ABS Sometimes used to denote an abstract (as in an abstract or summary of a scientific paper) AutoBackup
ACA Project Manager Workbench file
ACA HTTP animation file (Microsoft Agent)
ACB ACBM Graphic image
ACC DR-DOS Viewmax file
ACD Character definiton file (Microsoft Agent)
ACE ACE Archiver Compression file
ACF HTTP character file (Microsoft Agent)
ACI ACI development appraisal (ACIWEB)
ACL Corel Draw 6 keyboard accelerator file
ACM Windows system directory file
ACM Interplay compressed sound file (Fallout 1,2, Baulder’s Gate)
ACM Dynamic Link Library (DLL)
ACP Microsoft Office Assistant Preview file
ACR American College of Radiology file
ACS Character structered storage file (Microsoft Agent)
ACT Microsoft Office Assistant Actor file
ACT FoxPro Foxdoc Action Diagram
ACT Action Presentation
ACT Documenting wizard action diagram (Microsoft Visual FoxPro)
ACV Used to Compress and decompress audio data
AD After Dark screensaver
Ada Ada source text file (non-GNAT)
ADB Ada source text body file (GNAT)
ADB HP 100LX Organizer Appointment database
ADC Scanstudio 16 color Bitmap Graphic file
ADD OS/2 adapter driver file used in the boot process
ADF Amiga disk file
ADI AutoCAD device-independent binary plotter file
ADL QEMM Mca adaptor description library
ADM After Dark MultiModule screensaver (Microsoft)
ADM Windows NT policy template
ADN Lotus 1-2-3 Add-In file
ADP Dynamic Page file (AOLserver)
ADP FaxWorks Faxmodem setup file
ADP Astound Dynamite file
ADR After Dark Randomizer screensaver
ADR Smart Address address book
ADS Ada source text specification file (GNAT)
ADT HP NewWave datafile for card applications
ADT AdTech Fax file
ADX Dynazip Active Delivery script
ADX Lotus Approach dBase Index
ADX Archetype Designer Document
ADZ Packed ADF file (Extracts with WinZip)
AE Author/Editor file (SoftQuad)
AEP ArcExplorer project file
AF2 ABC FlowCharter 2.0 Flowchart
AF3 ABC Flowchart
AFC Apple Sound file
AFI Truevision Bitmap graphic
AFM Adobe metrics
AFM HP NewWave Cardfile application
AG Applix graphic
AI Adobe Illustrator drawing
AI Corel Trace drawing
AIF Audio Interchange File, a sound format used by Silicon Graphics and Macintosh applications
AIFC Similar to AIF (compressed)
AIFF Similar to AIF
AIM AOL Instant Messenger Launch file
AIN AIN Compressed archive
AIO APL transfer file
AIS ACDSee Image Sequence
AIS Velvet Studio Instruments file
AIS Xerox Arry of Intensity Samples Graphic
AIX HP NewWave Cardfile Application data
AKW Contains all A-keywords in the RoboHELP Help Project Index Designer not associated with topics
ALAW European Telephony audio
ALIAS Alias Image
ALB JASC Image Commander album
ALI Document file (SAP proprietary format)
ALL Arts & Letters Library
ALL WordPerfect for Windows General printer information file
ALS Alias Image
ALT WordPerfect Library Menu
AM Applix SHELF Macro
AMF Music file (Advanced Module Format)
AMF DSMIA/Asylum module music (Crusader,No Remorse,Aladdin)
AMG AMGC Compressed archive
AMG ACTOR System image
AMI Annotation file (Cocreate SolidDesigner)
AMS Velvet Studio music module (MOD) file
AMS Extreme’s Tracker module
AN Text file (Sterling Software) (Groundworks COOL Business Team Model)
ANC Canon Computer Pattern Maker file that is a selectable list of pattern colors
ANI Microsoft Windows Animated cursor
ANM DeluxPaint Animation
ANN Windows 3.x Help annotation
ANS ANSI Text file
ANT SimAnt for Windows saved game
AOS Nokia 9000 Add-on software
AOT Applicatio binary object template file (ZenWorks snAPPshot)
AP Applix Presents file
AP WHAP Compressed Amiga archive
APC Compiled application file (Centura Team Developer)
APC Lotus 1-2-3 Printer driver
APD Dynamic application library file (Centura Team Developer)
APD Lotus 1-2-3 Printer driver
APF Lotus 1-2-3 Printer driver
APF Project file (Allaire) (Created by Homesite)
API Application Program Interface; used by Adobe Acrobat
API Lotus 1-2-3 Printer driver
APL Application library file (Centura Team Developer)
APL APL Workspace file
APP Normal mode application file (Centura Team Developer)
APP Symphony Add-in Application
APP Generated application or active document (Microsoft Visual FoxPro)
APP dBase Application Generator Object
APP DR-DOS Executable Application
APP FoxPro Generated Application
APR ArcView project file
APR Employee Appraiser Performance Review file
APR Lotus Approach 97 View file
APS Microsoft Visual C++ file
APS Advanced patching systems with error checking, (Similar to IPS)
APT Lotus Approach Data view file
APT Text mode application file (Centura Team Developer)
APX Lotus Approach Paradox-Specific information file
APX Borland C++ Appexpert database
AQ Applix data
ARC LH ARC (old version) compressed archive
ARC SQUASH Compressed archive
ARF Automatic Response file
ARI ARI Compressed archive
ARI Aristotle audio file
ARJ Robert Jung ARJ compressed archive (ARJ)
ARK ARC File Archiver CPM/Port archive
ARL AOL v4.0 organizer file
ARR Atari Cubase Arrangement
ART Xara Studio drawing
ART Canon Crayola art
ART Clip Art
ART Ray Tracer file
ART First Publisher Raster graphic
ART AOL Image file compressed using the Johson-Grace compression algorithm
ARX ARX Compressed Archive
AS Applix Spreadsheet
ASA Microsoft Visual InterDev file
ASC ASCII text file
ASC PGP armored encrypted file
ASD WinWord AutoSave file
ASD Lotus 1-2-3 Screen driver
ASD Microsoft Advanced Streaming Format (ASF) description file; opens with NSREX
ASD Astound Presentation
ASE Velvet Studio Sample file
ASF Music file (Electronic Arts)
ASF Microsoft Advanced Streaming Format
ASF StratGraphics Datafile
ASF Lotus 1-2-3 Screen font
ASH TASM 3.0 Assembly language header
ASI Borland C++/Turbo C Assembler Include file
ASM Assembler Language source file
ASM Pro/E assembly file
ASO Astound Dynamite Object
ASP Active Server Page (an HTML file containing a Microsoft server-processed script)
ASP Procomm Plus setup and connection script
ASP Astound Presentation
AST Astound multimedia file
AST Claris Works “assistant” file
ASV DataCAD Autosave file
ASX Cheyenne Backup script
ASX Microsoft Advanced Streaming Redirector file
ASX Video file
AT2 Aldus Persuasion 2.0 Auto Template
ATM Adobe Type Manager data/info file
ATT AT&T Group 4 bitmap
ATW AnyTime Deluxe for Windows personal information manager file from Individual Software MultiModule screensaver
AU Sun/NeXT/DEC/UNIX sound file
AU Audio U-law (pronounced mu-law)
AUD Audio file (Westwood Studios) (Kyrandia 3,C&C,RedAlert,C&C:TS)
AUX TeX/LaTeX Auxilliary Reference file
AUX ChiWriter Auxilliary Dictionary file
AVA Avagio Publication
AVB Inculan Anti-Virus virus infected file
AVI Microsoft Audio Video Interleaved file for Windows movie
AVR Audio Visual Research file
AVS Application Visualization System file
AVS Stardent AVS-X Image
AVX File Extension (ArcView)
AW HP AdvanceWrite Text file
AW Applix Words file
AWD FaxView Document image
AWK AWK Script/Program
AWM Animation Works Movie
AWR Telsis file for digitally stored audio
AWS StatGraphics Data file
AXL ArcIMS XML project file
AXT ASCII application object template (ZenWorks snAPPshot)
AXX ARJ compressed file from a multi-volume archive (xx = a number from 01 to 99)
A3L Authorware 3.x library
A4L Authorware 4.x library
A5L Authorware 5.x library
A3M Authorware MacIntosh file (unpackaged)
A4M Authorware MacIntosh file (unpackaged)
A4P Authorware file (packaged without runtime)
A3W Authorware Windows file (unpackaged)
A4W Authorware Windows file (unpackaged)
A5W Authorware Windows file (unpackaged
B Applause Batch list
BAD Oracle bad file
BAK Backup file
BAL Ballade Music score
BAR dBase Application Generator Horizontal menu object
BAS BASIC source code
BAT Batch file
BB Papyrus Database backup
BBL TeX/BibTeX Bibliographic reference file
BBM Deluxe Paint Bitmap image
BBS Bulletin Board Sytem text
BCH Batch Process Object (dBase Application Generator)
BCH Datalex Entry Point 90 Data file
BCM Microsoft Works Communications file
BCO Bitstream Outline font description file
BCP Borland C++ Makefile
BCW Borland C++ 4.5 Environment settings file
BDB Microsoft Works Dababase file
BDF West Point Bridge Designer file
BDF Egret Datafile
BDR Microsoft Publisher Border
BEZ Bitstream Outline font description
BF2 Bradford 2 Font
BFC Windows 95 Briefcase Document
BFM Font Metrics file (Unix/Mainframe)
BFX Fax document file (BitFax)
BG Microsoft Backgammon Game file
BGA OS/2 Graphic array
BGI Borland Graphics Interface Driver
BGL Microsoft Flight Simulator Scenery file
BHF pcAnywhere Host file
BI Binary file
BIB Bibliography file (ASCII)
BIB TeX/BibTeX Literature Database
BIB Database
BIF GroupWise initialization file
BIF Image Capture Board Binary Image black & white graphic
BIFF XLITE 3D file
BIN Binary file
BIO OS/2 Bios file
BIT X11 Bitmap
BK Backup file (Generic)
BK JetFax Faxbook file
BK$ Backup file (Generic)
BK! WordPerfect for Windows Document backup
BK1 WordPerfect for Windows Timed backup file for document window 1
BK2 WordPerfect for Windows Timed backup file for document window 2
BK3 WordPerfect for Windows Timed backup file for document window 3
BK4 WordPerfect for Windows Timed backup file for document window 4
BK5 WordPerfect for Windows Timed backup file for document window 5
BK6 WordPerfect for Windows Timed backup file for document window 6
BK7 WordPerfect for Windows Timed backup file for document window 7
BK8 WordPerfect for Windows Timed backup file for document window 8
BK9 WordPerfect for Windows Timed backup file for document window 9
BKP TurboVidion Dialog Designer Backup
BKS IBM BookManager Read bookshelf file
BKS Microsoft Works Spreadsheet Backup
BKW FontEdit Fontset mirror image
BLB Resource archive (DreamWorks),(Neverhood)
BLD BASIC Bloadable picture file
BLK Alias Wavefront Image
BLK WordPerfect for Windows Temporary file
BM Windows system Bitmap
BMF Corel Gallery file
BMK Windows Help bookmark
BMP Windows or OS/2 bitmap
BM1 Apogee BioMenace data
BN Instrument bank file (AdLib)
BNK Sound effects bank file (Electronic Arts)
BNK Instrument Bank file (AdLib)
BOL Compressed archive library file (Microsoft Booasm.arc)
BOM Bill of materials file (Orcad Schematic Capture)
BOO Microsoft Booasm.arc Compressed archive
BOOK Adobe FrameMaker Book
BOX Lotus Notes file
BPC Business Plan Toolkit Chart
BPL Borland Delphi 4 packed library
BPS Microsoft Works Document
BPT CorelDraw Bitmap fills file
BPX Truevision Targa Bitmap
BQY BrioQuery file
BR Bridge Script
BRD Eagle Layout file
BRK Brooktrout Fax-Mail file
BRW Application file associated with financial institution(s) loan applications
BRX A file for browsing an index of multimedia options
BRZ DbBRZ file for very large Db backup or restore
BSA BSARC Compressed archive
BSC Apple II Compressed archive
BSC Fortran Pwbrmake Object
BSC MS Developer Studio (MSDev) browser information
BSP Quake map file
BS1 Apogee Blake Stone data file
BS_ Microsoft Bookshelf Find Menu shell extension
BTM Batch file used by Norton Utilities
BTR Database file (Btrieve 5.1)
BUD Backup disk for Quicken
BUG Bugs and Problems file
BUN CakeWalk Audio Bundle (a MIDI program)
BUP Backup
BUT Buttons! Button definition
BUY Movie data file
BV1 WordPerfect for Windows Overflow file below insert point in document 1
BV2 WordPerfect for Windows Overflow file below insert point in document 2
BV3 WordPerfect for Windows Overflow file below insert point in document 3
BV4 WordPerfect for Windows Overflow file below insert point in document 4
BV5 WordPerfect for Windows Overflow file below insert point in document 5
BV6 WordPerfect for Windows Overflow file below insert point in document 6
BV7 Wordperfect for Windows Overflow file below insert point in document 7
BV8 WordPerfect for Windows Overflow file below insert point in document 8
BV9 WordPerfect for Windows Overflow file below insert point in document 9
BW SGI Black and White image file
BW Silicon Graphics Raw red,green and blue bytes file
BWB Visual Baler Spreadsheet application
BWR Kermit Beware buglist
BWV Business Wave file
BYU BYU Movie
BZ Bzip compressed file (Inix)
BZ2 Bzip compressed file (Unix) (replaces Bz)
B1N 1st Reader Mono and color binary screen image
B30 ABC Ventura publisher printer font
B4 Helix Nuts and Bolts file
B8 Raw graphic file (Piclab Plane II)
B_W Atari/Macintosh black and white graphic
B&W Atari/Macintosh black and white graphic
B&W 1st Reader Mono binary screen image