ABK

Corel Draw AutoBackup

ACL

Corel Draw 6 keyboard accelerator

ACM

Used by Windows in the system directory

ACP

Microsoft Office Assistant Preview file

ACT

Microsoft Office Assistant Actor file

ACV

OS/2 drivers that compress and decompress audio data

AD

After Dark screensaver

ADB

Appointment database used by HP 100LX organizer

ADD

OS/2 adapter drivers used in the boot process

ADM

After Dark MultiModule screensaver

ADP

Used by FaxWorks to do setup for fax modem interaction

ADR

After Dark Randomizer screensaver

AFM

Adobe font metrics

AF2

ABC Flowchart file

AF3

ABC Flowchart file

AI

Adobe Illustrator drawing

AIF

Apple Mac AIFF sound

ALB

JASC Image Commander album

ALL

Arts & Letters Library

AMS

Velvert Studio music module (MOD) file

ANC

Canon Computer Pattern Maker file that is a selectable list of pattern colors

ANI

Animated Cursor

ANS

ANSI text

API

Application Program Interface file; used by Adobe Acrobat

APR

Lotus Approach 97 file

APS

Microsoft Visual C++ file

ARC

LH ARC (old version) compressed archive

ARJ

Robert Jung ARJ compressed archive

ART

Xara Studio drawing

ART

Canon Crayola art file

ASA

Microsoft Visual InterDev file

ASC

ASCII text

ASD

WinWord AutoSave

ASM

Assembler language source file

ASP

Active Server Page (an HTML file containing a Microsoft server-processed script)

ASP

Procomm Plus setup and connection script

AST

Claris Works "assistant" file

ATT

AT&T Group 4 bitmap

AVI

Microsoft Video for Windows movie

AWD

FaxView document

BAK

Backup file

BAS

BASIC code

BAT

Batch file

BFC

Windows 95 Briefcase document

BG

Backgammon for Windows game

BI

Binary file

BIF

GroupWise initialization file

BIN

Binary file

BK

Sometimes used to denote backup versions

BK$

Also sometimes used to denote backup versions

BKS

An IBM BookManager Read bookshelf

BMK

An A bookmark file

BMP

Windows or OS/2 bitmap

BM1

Apogee BioMenace data file

BRX

A file for browsing an index of multimedia options 

BSP

Quake map

BS1

Apogee Blake Stone data file

BTM

Batch file used by Norton Utilities

B4

Helix Nuts and Bolts file

C

C code

CAB

Microsoft cabinet file (program files compressed for software distribution)

CAL

CALS Compressed Bitmap

CAL

Calendar schedule data

CAS

Comma-delimited ASCII file

CAT

IntelliCharge categorization file used by Quicken

CB

Microsoft clean boot file

CCB

Visual Basic Animated Button configuration

CCF

Multimedia Viewer configuration file used in OS/2

CCH

Corel Chart

CCM

Lotus CC:Mail "box" (for example, INBOX.CCM)

CDA

CD Audio Track

CDF

Microsoft Channel Definition Format file

CDI

Phillips Compact Disk Interactive format

CDR

Core Draw drawing

CDT

Corel Draw template

CDX

Corel Draw compressed drawing

CEL

CIMFast Event Language file

CFG

Configuration file

CGI

Common Gateway Interface script file

CGM

Computer Graphics Metafile

CH

OS/2 configuration file

CHK

File fragments saved by Windows Disk Defragmenter or ScanDisk

CHP

Ventura Publisher chapter

CIL

Clip Gallery download package

CIM

Sim City 200 file

CIN

OS/2 change control file that tracks changes to an INI file

CK1

iD/Apogee Commander Keen 1 data file

CK2

iD/Apogee Commander Keen 2 data file

CK3

iD/Apogee Commander Keen 3 data file

CK4

iD/Apogee Commander Keen 4 data file

CK5

iD/Apogee Commander Keen 5 data file

CK6

iD/Apogee Commander Keen 6 data file

CLASS

Java class

CLP

Windows Clipboard file

CLS

Visual Basic Class Module

CMD

Command file for Windows NT (similar to a DOS .BAT file)

CMD

DOS CP/M command file

CMD

dBase-II program file

CMF

Corel Metafile

CMP

JPEG Bitmap

CMP

Address document

CMV

Corel Move animation

CMX

Corel Presentation Exchange image

CNF

Configuration file used by Telnet, Windows, and other applications

CNM

Windows application menu options and setup file

CNQ

Compuworks Design Shop file

CNT

Windows (or other) system content files for the help index and other purposes

COB

trueSpace2 object

COD

Microsoft C compiler output as displayable assembler with original C as comments

COM

Command file (program)

CPD

Fax Cover document

CPE

Fax Cover document

CPI

Microsoft MS-DOS code page information file

CPL

Control Panel extension

CPL

Corel colour palette

CPP

C++ code

CPR

Corel Presents Presentation

CPT

Corel Photo-Paint image

CPX

Corel Presentation Exchange Compressed drawing

CRD

Cardfile file

CRP

Corel Presents Run-Time Presentation

CRT

Certificate file

CSC

Corel Script

CSP

PC Emcee On-Screen image

CSV

Comma-separated values file

CT

Scitex CT Bitmap

CTL

Used in general to mean a file containing control information. 

CUE

Microsoft Cue Cards data

CUR

Windows Cursor

CUT

Dr Halo bitmap

CV

Corel Versions archive

CV

Microsoft CodeView information screen

CWK

Claris Works data file

CWS

Claris Works template

CXX

C++ source code file

DAT

Data file

DAT

WordPerfect Merge Data

DBF

Aston-Tate dBASE database

DBX

DataBeam image

DCR

Shockwave file

DCS

Desktop Color Separation file

DCX

Fax image (based on PCX)

DDF

BTRIEVE database

DEF

SmartWare II data file

DEF

C++ Definition

DER

Certificate file

DIB

Device-Independent Bitmap

DIC

Dictionary

DIF

Data Interchange Format spreadsheet

DIR

Macromedia Director file

DIZ

Description file

DLG

C++ Dialogue Script

DLL

Dynamic-Link Library

DMF

X-Trakker music module (MOD) file

DOC

FrameMaker or FrameBuilder document

DOC

WordStar document

DOC

WordPerfect document

DOC

Microsoft Word document

DOT

Microsoft Word document Template

DPR

Borland Delphi project header file

DRV

Driver

DRW

Micrografx Designer/Draw

DSG

DooM saved game

DSM

Dynamic Studio music module (MOD) file

DSP

Microsoft Developer Studio project

DSQ

Corel QUERY file

DSW

Microsoft Developer Studio workspace

DWG

AutoCAD drawing eXchange format

DXF

AutoDesk Drawing Interchange format

EMF

Enhanced Windows Metafile

ENC

Encore file

EPS

Encapsulated PostScript image

ER1

ERWin file

ERX

ERWin file

EVY

Envoy document

EWL

Microsoft Encarta document

EXE

Executable file (program)

F

FORTRAN file

F77

FORTRAN file

F90

FORTRAN file

FAR

Farandole Composer music module (MOD) file

FAV

Microsoft Outlook navigation bar

FAX

FAX Type image

FH3

Aldus Freehand 3 drawing

FIF

Fractal image file

FITS

CCD camera image

FLC

AutoDesk FLIC animation

FLI

AutoDesk FLIC animation

FLT

Corel filter

FLT

StarTrekker music module (MOD) file

FMB

Oracle binary source code for form, version 4.0 and later

FMT

Oracle text format of form, version 4.0 and later

FMT

Microsoft Schedule+ print file

FMX

Oracle executable form, version 4.0 and later

FOG

Fontographer font

FON

System font

FOR

FORTRAN file

FOT

Font-related file

FP

FileMaker Pro file

FP1

Flying Pigs for Windows data file

FP3

FileMaker Pro file

FPX

FlashPix bitmap

FRM

Form

FRM

FrameMaker or FrameBuilder document

FRM

Oracle executable form version 3.0 and earlier

FRM

Visual Basic form

FRM

WordPerfect Merge form

FRX

Visual Basic form stash file

GAL

Corel Multimedia Manager album

GCP

Ground Control Point file used in image processing of remote sensing data . 

GED

Graphic Environment Document (drawing)

GEM

GEM metafile

GEN

Ventura-Generated text file

GFC

Patton&Patton Flowcharting 4 flowchart file

GFI

Genigraphics Graphics Link presentation

GFX

Genigraphics Graphics Link presentation

GID

Windows 95 global index file (containing help status)

GIF

CompuServe bitmap

GIM

Genigraphics Graphics Link presentation

GIX

Genigraphics Graphics Link presentation

GNA

Genigraphics Graphics Link presentation

GNX

Genigraphics Graphics Link presentation

GRA

Microsoft Graph

GRD

Grid file, used in image processing of remote sensing data often to form map projections. 

GRP

Program Manager Group

GTK

Graoumftracker (old) music module (MOD) file

GT2

Graoumftracker (new) music module (MOD) file

GWX

Genigraphics Graphics Link presentation

GWZ

Genigraphics Graphics Link presentation

GZ

Unix Gzip compressed file

H

C program header

HED

HighEdit document

HEL

Microsoft Hellbender saved game

HEX

Macintosh BinHex 2.0 file

HGL

HP Graphics Language drawing

HLP

Help file

HOG

Lucas Arts Dark Forces WAD file

HPJ

Visual Basic Help Project

HPP

C++ program header

HQX

Macintosh BinHex 4.0 file

HST

History file

HT

HyperTerminal

HTM

Hypertext document

HTML

Hypertext document

HTX

Extended HTML template

ICA

Citrix file

ICB

Targa bitmap

ICM

Image Color Matching profile file

ICO

Windows Icon

IDD

MIDI Instrument Definition

IDQ

Internet Data Query file

IFF

Amiga ILBM

IGF

Inset Systems metafile

IIF

QuickBooks for Windows interchange file

IMA

WinImage file

IMG

GEM image

INC

Assembler language or Active Server include file

INF

Information file

INI

Initialization file

INP

Oracle source code for form, version 3.0 and earlier

INS

InstallShield install script

INS

X-Internet sign-up file

ISO

Lists the files on a CD-ROM; based on the ISO 9660 CD-ROM file system standard

ISP

X-Internet sign-up file

ISU

InstallShield uninstall script

IT

Impulse Tracker music module (MOD) file

IW

Idlewild screensaver

JAR

Java ARchive file (a compressed file for applets and related files)

JAVA

Java source code

JBF

Paint Shop Pro image browser file

JFF

JPEG bitmap

JIF

JPEG bitmap

JMP

SAS JMPDiscovery chart-to-statistics file

JN1

Epic MegaGames Jill of the Jungle data file

JPEG

JPEG bitmap

JPG

JPEG bitmap

JS

JavaScript source code

JTF

JPEG bitmap

KDC

Kodak Photo-Enhancer

KFX

KoFax Group 4 image

KYE

Kye game data

LBM

Deluxe Paint bitmap

LDB

Microsoft Access lock file

LEG

Legacy document

LHA

Alternate file suffix for LZH

LIB

Library

LIS

Output file produced by a Structured Query Reporting (SQR) program

LOG

Log file

LPD

Helix Nuts and Bolts file

LRC

Intel Video Phone file

LST

List file

LWO

Lightwave Object file

LWP

Lotus Wordpro 96/97 file

LZH

LH ARC compressed archive

LZS

Skyroads data file

M3D

Corel Motion 3D animation

MAC

MacPaint image

MAD

Microsoft Access module

MAF

Microsoft Access Form

MAK

Visual Basic or MS Visual C++ Project

MAM

Microsoft Access Macro

MAP

Map file

MAP

Duke Nukem 3D WAD game file

MAQ

Microsoft Access Query

MAR

Microsoft Access Report

MAS

Lotus Freelance Graphics Smartmaster file

MAT

Microsoft Access Table

MAX

Paperport file

MAZ

Hover maze data

MB1

Apogee Monster Bash data file

MCC

Dialer10 calling card

MCS

MathCAD image

MCW

Microsoft Word for Macintosh document

MDA

Microsoft Access add-in

MDB

Microsoft Access database

MDE

Microsoft Access MDE file

MDL

Digital Tracker music module (MOD) file

MDL

Quake model file

MDN

Microsoft Access blank database template

MDW

Microsoft Access Workgroup

MDZ

Microsoft Access wizard template

MED

Music Editor, OctaMED music module (MOD) file

MER

Format for interchanging spreadsheet/database data; recognized by Filemaker, Excel, and others

MET

Presentation Manager metafile

MI

Miscellaneous

MIC

Microsoft Image Composer file

MID

MIDI music

MMF

Microsoft Mail File

MMM

Microsoft Multimedia Movie

MOD

FastTracker, StarTrekker, Noise Tracker (etc.) music module file

MOD

Microsoft Multiplan spreadsheet

MOV

QuickTime for Windows movie

MPE

MPEG animation

MPEG

MPEG animation

MPG

MPEG animation

MPP

Microsoft Project file

MPP

CAD drawing file format

MP3

MPEG Audio Layer 3 (AC3) file

MSG

Microsoft Mail message

MSN

Microsoft Network document

MSP

Microsoft Paint bitmap

MTM

MultiTracker music module (MOD) file

MUS

Music

MVB

Microsoft Multimedia Viewer file

MWP

Lotus Wordpro 97 Smartmaster file

NAP

NAP Metafile

NCB

Microsoft Developer Studio file

NSF

Lotus Notes database

NST

Noise Tracker music module (MOD) file

NTF

Lotus Notes database template

OBD

Microsoft Office binder template

OBD

Microsoft Office Binder

OBJ

Object file

OBZ

Microsoft Office Binder Wizard

OCX

Microsoft Object Linking and Embedding custom control

OFN

Microsoft Office FileNew file

OFT

Microsoft Outlook template

OKT

Oktalyzer music module (MOD) file

OLB

OLE Object Library

OLE

OLE object

OPT

Microsoft Developer Studio file

ORG

Lotus Organiser file

OR2

Lotus Organiser 2 file

OR3

Lotus Organiser 97 file

P10

Tektronix Plot 10 drawing

PAB

Microsoft Personal Address Book

PAK

Quake WAD file

PAL

Windows colour palette

PAT

Corel Draw pattern

PBK

Microsoft Phonebook

PBM

Portable Bitmap

PCD

Kodak Photo-CD image

PCL

HP Laserjet bitmap

PCS

PICS animation

PCT

Macintosh PICT drawing

PCX

ZSoft PC Paintbrush bitmap

PDF

Adobe Acrobat Portable Document Format or Netware Printer Definition File

PDF

Package Definition File from Microsoft Systems Management Server

PDQ

Patton&Patton Flowcharting PDQ Lite file

PFA

Type 1 font (ASCII)

PFB

Type 1 font (binary)

PFC

PF Component

PFM

Printer Font Metrics

PGL

HP Plotter drawing

PGM

Portable Graymap (bitmap)

PIC

PC Paint bitmap

PIC

Lotus picture

PIC

Macintosh PICT drawing

PIF

Program Information File

PIF

IBM PIF drawing

PIG

Lucas Arts Dark Forces WAD file

PIN

Epic Pinball data file

PIN

Epic Pinball data file

PIX

Inset Systems bitmap

PJ

MKS Source Integrity file

PKG

Microsoft Developer Studio application extension (similar to a DLL file)

PL

Perl program

PLT

HPGL Plotter drawing

PLT

AutoCAD Plot drawing

PM5

Pagemaker 5.0 file

PM6

Pagemaker 6.0 file

P65

Pagemaker 6.5 file

PNG

Portable Network Graphics bitmap

PNG

Paint Shop Pro Browser catalogue

PNT

MacPaint graphic file

POT

Microsoft PowerPoint Template

PP4

Picture Publisher 4 bitmap

PPA

Microsoft PowerPoint Add-in

PPM

Portable Pixelmap bitmap

PPS

Microsoft PowerPoint slide show

PPT

Microsoft PowerPoint presentation

PRE

Lotus Freelance presentation

PRF

Windows system file

PRN

Print Table (space delimited text)

PRS

Harvard Graphics for Windows presentation

PRZ

Lotus Freelance Graphics 97 file

PS

Postscript Interpreted drawing

PSD

Adobe Photoshop bitmap

PST

Microsoft Outlook Personal Folder File

PTM

Polytracker music module (MOD) file

PUB

Ventura Publisher publication

PUB

Microsoft Publisher document

PWD

Microsoft Pocket Word document

PWZ

Microsoft PowerPoint Wizard

PXL

Microsoft Pocket Excel spreadsheet

QAD

PF QuickArt Document

QBW

QuickBooks for Windows file

QDT

Quick Books data file from the Quicken UK Accountancy/Tax/Invoice program

QLB

Quick Library

QRY

Microsoft Query

QT

QuickTime Movie

QTM

QuickTime Movie

QXD

Quark XPress file

R

Pegasus Mail resource file

RA

Real Audio sound

RAM

Real Audio sound

RAS

Sun Raster Images bitmap

RAW

Raw File Format (bitmap)

RC

Microsoft Visual C++ Resource Script

REC

Recorder macro

REG

Registration file

RES

Microsoft Visual C++ Resource

RFT

RFT-DCA

RLE

Run-Length Encoded bitmap

RM

Real Audio video file

RMI

MIDI music

ROV

Rescue Rover data file

RPT

Microsoft Visual Basic Crystal Reports file

RTF

Rich Text Format document

RTM

Real Tracker music module (MOD) file

SAM

Ami Professional document

SAV

Saved game file

SCC

Microsoft Source Safe file

SCD

Matrix/Imapro SCODL slide image

SCD

Microsoft Schedule+ 7

SCH

Microsoft Schedule+ 1

SCN

trueSpace2 scene

SCP

Dial-Up Networking Script

SCR

Windows screensaver

SCR

Fax image

SCT

Scitex CT bitmap

SC2

Microsoft Schedule+ 7

SDL

SmartDraw library

SDR

SmartDraw drawing

SDT

SmartDraw template

SEA

Self-expanding archive (used by Stuffit for Mac files and possibly by others)

SEP

Tagged Image File Format (TIFF) bitmap

SHB

Corel Show presentation

SHB

Document shortcut file

SHG

Hotspot bitmap

SHS

Shell scrap file

SHW

Corel Show presentation

SIT

Stuffit archive of Mac files

SLK

Symbolic Link (SYLK) spreadsheet

SND

NeXT sound

SND

Mac Sound Resource

SQC

Structured Query Language (SQR) common code file

SQR

Structured Query Language (SQR) program file

STM

Scream Tracker music module (MOD) file

STY

Ventura Publisher style sheet

SVX

Amiga 8SVX sound

SYS

System file

S3M

Scream Tracker 3 music module (MOD) file

TAR

Tape Archive

TAZ

Unix Gzip/Tape Archive

TEX

Texture file

TGA

Targa bitmap

TGZ

Unix Gzip/Tape Archive

THEME

Windows 95 Desktop Theme

THN

Graphics Workshop for Windows thumbnail

TIF

Tag Image File Format (TIFF) bitmap

TIFF

Tag Image File Format (TIFF) bitmap

TIG

Tiger file, used by US government to distribute maps

TLB

OLE Type Library

TMP

Windows temporary file

TRM

Terminal file

TRN

MKS Source Integrity project usage log

TTF

TrueType font

TWF

TabWorks file

TWW

Tagwrite Template

TX8

MS-DOS Text

TXT

Text

T2T

Sonata CAD modelling software file

UDF

Windows NT Uniqueness Database File

ULT

Ultratracker music module (MOD) file

URL

Internet shortcut

USE

MKS Source Integrity file

VBP

Visual Basic Project

VBW

Microsoft Visual Basic workspace

VBX

Visual Basic custom control

VCF

Vevi Configuration File; defines objects for use with Sense8's WorldToolKit

VDA

Targa bitmap

VI

Virtual Instrument file from National Instruments LABView product

VLB

Corel Ventura Library

VOC

Creative Labs Sound Blaster sound

VP

Ventura Publisher publication

VSD

Visio drawing (flow chart or schematic)

VST

Targa bitmap

VSW

Visio Workspace file

VXD

Microsoft Windows virtual device driver

WAD

Large file for Doom game containing video, player level, and other information

WAV

Windows Waveform sound

WB1

QuattroPro for Windows spreadsheet

WB2

QuattroPro for Windows spreadsheet

WBK

Microsoft Word Backup

WBL

Argo WebLoad II upload file

WCM

WordPerfect Macro

WDB

Microsoft Works database

WEB

CorelXara Web document

WGP

Wild Board Games data file

WID

Ventura width table

WIL

WinImage file

WIZ

Microsoft Word Wizard

WK1

Lotus 123 versions 1 & 2 spreadsheet

WK3

Lotus 123 version 3 spreadsheet

WK4

Lotus 123 version 4 spreadsheet

WKS

Lotus 123 Worksheet spreadsheet

WKS

Microsoft Works document

WLF

Argo WebLoad I upload file

WLL

Microsoft Word Add-In

WMF

Windows Metafile

WOW

Grave Composer music module (MOD) file

WP

WordPerfect document

WPW

Novel PerfectWorks document

WP4

WordPerfect 4 document

WP5

WordPerfect 5 document

WP6

WordPerfect 6 document

WPD

WordPerfect Demo

WPD

WordPerfect Document

WPG

WordPerfect Graphic

WPS

Microsoft Works document

WPT

WordPerfect Template

WQ1

QuattroPro/DOS spreadsheet

WQ2

QuattroPro/DOS version 5 spreadsheet

WRI

Write document

WRL

Virtual Reality model

WS1

WordStar for Windows 1 document

WS2

WordStar for Windows 2 document

WS3

WordStar for Windows 3 document

WS4

WordStar for Windows 4 document

WS5

WordStar for Windows 5 document

WS6

WordStar for Windows 6 document

WS7

WordStar for Windows 7 document

WSD

WordStar 2000 document

WVL

Wavelet Compressed Bitmap

XAR

Corel Xara drawing

XLA

Microsoft Excel add-in

XLB

Microsoft Excel toolbar

XLC

Microsoft Excel chart

XLD

Microsoft Excel dialogue

XLK

Microsoft Excel backup

XLM

Microsoft Excel macro

XLS

Microsoft Excel worksheet

XLT

Microsoft Excel template

XLV

Microsoft Excel VBA module

XLW

Microsoft Excel workbook / workspace

XM

FastTracker 2, Digital Tracker music module (MOD) file

XR1

Epic MegaGames Xargon data file

XTP

XTree data file

XY3

XYWrite III document

XY4

XYWrite IV document

XYP

XYWrite III Plus document

XYW

XYWrite for Windows 4.0 document

YAL

Arts & Letters clipart library

YBK

Microsoft Encarta Yearbook

Z

Unix Gzip

ZIP

Zip file

ZOO

An early compressed file format

000-999

Used to number old versions of files and number related data files 

12M

Lotus 123 97 Smartmaster file

123

Lotus 123 97 file

2GR and 3GR

VGA Graphics driver/configuration files under Windows

386

A file for use in an 80386 or higher microprocessor

669

Composer 669, Unis Composer music mod file

#01 and higher

A method of numbering picture files for a roll of film that has been scanned 

$$$

Used by OS/2 to keep track of archived files

@@@

Screen files used in the installation and instruction on use of applications