3GP	Audio and video container format developed by the 3rd Generation Partnership Project (3GPP); designed as a multimedia format for transmitting audio and video files between 3G cell phones and over the Internet; commonly used by mobile phones that support video capture.
	
7Z	"Compressed archive created with Igor Pavlov's 7-Zip file compression utility; uses open-source LZMA compression, which has a high compression ratio and can include strong AES-256 (256-bit) encryption; supports Unicode file names, archive header compression, and file sizes up to 16,000,000,000 GB."
	
	"While 7z compression uses the LZMA method by default, the 7z format also supports the PPMD, BCJ, BCJ2, BZip2, and Deflate compression methods."
	
AMR	"Compressed audio format developed by Ericsson; used by many 3G cell phones for voice recordings such as MMS messages; incorporates the Algebraic Code Excited Linear Prediction (ACELP) algorithm, which is designed to efficiently compress human speech audio."
	
ARW	Raw image file captured by Sony digital cameras; can be converted to more standard image file types using various programs; based on the .TIFF file format.
	
ASP	"Server-generated Web page that may contain scripts written in VBScript, C#, or JavaScript; parsed on the server, which generates HTML that is sent to the client's browser; commonly used by ASP.NET sites and websites hosted on Microsoft IIS-based servers."
	
	"Since ASP pages are processed on the server, website visitors do not see the actual ASP code"
	
ASPX	Server-generated Web page that may contain VBScript or C# code; often created with Microsoft Visual Web Developer and is designed for the Microsoft ASP.NET framework; scripts within the page are processed on the Web server and the resulting HTML is sent to the user's Web browser.
	
	"ASPX pages are also called "".NET Web forms."" They can be identified in a Web browser when the URL in the address field ends in "".aspx""."
	
AVI	Video container or wrapper format created by Microsoft; stores video data that may be encoded in a variety of codecs; typically uses less compression than similar formats such as .MPEG and .MOV.
	
BAT	BAT files can be manually created and edited to automate tasks and perform repetitive operations.
	
BMP	"Uncompressed raster image comprised of a rectangular grid of pixels; contains a file header (bitmap identifier, file size, width, height, color options, and bitmap data starting point) and bitmap pixels, each with a different color."
	
	"BMP files may contain different levels of color depths per pixel, depending on the number of bits per pixel specified in the file header. They may also be stored using a grayscale color scheme."
	
C	"Source code for a C or C++ program; may include an entire program's source code, or may be one of may source files referenced within a programming project; can be edited using a basic text editor, but will not show syntax highlighting like most software development programs do."
	
	"C++ is the programming language used for creating many of today's software programs. Some Unix compilers use a lowercase "".c"" extension for C and an upper case "".C"" extension for C++, although this convention is not common."
	
CF2	Common files Format 2
	
CFG	"Generic preference file that stores settings and configuration information; used by various programs, which means different CFG files may store data in different formats; typically should not be opened manually, but may be saved in a text format that can be viewed in a text editor; can sometimes be moved or deleted to revert to a program's default settings."
	
CR2	"Raw camera image created by Canon digital cameras; stores uncompressed image data exactly how it was captured by the CCD; can be adjusted for white balance and exposure using several image-editing software programs, including the software bundled with Canon digital camera purchases."
	
	"CR2 files are saved in a format based on the TIFF specification. Some earlier versions of Canon digital cameras also use the .CRW format, which is based on the Camera Image File Format (CIFF)."
	
CRW	"Uncompressed and unprocessed Camera RAW image file from a Canon digital camera; based the Camera Image File Format (CIFF), a standardized format developed for saving images."
	
CS	"Source code file used by Microsoft Visual C# (C Sharp) and C# .NET development software, which is included in Microsoft Visual Studio; often used for developing software components that are implemented distributed environments"
	
CSS	"Cascading Style Sheet (CSS) file used to format the contents of a Web page; contains customized, global properties for how to display HTML elements; can define the size, color, font, line spacing, indentation, borders, and location of HTML elements."
	
	CSS files are used to create a similar look and feel across websites. They also are used to reduce the amount of work and HTML code generated by consolidating display properties into a single file.
	
	CSS files are stored in a plain text format.
	
CSV	"File containing data sets separated by commas, where each new line represents a new database row, and each database row has one or more fields separated by a comma; can be organized into cells by a spreadsheet program or inserted into a database."
	
	CSV files are commonly used for transferring data between databases in a simple text-based format.
	
DEB	Standard Unix archive that contains two bzipped or gzipped archives; one for the installer control information and another for the actual data; typically used for software installation packages.
	
DNG	Universal RAW image format for saving digital photos in an uncompressed format; developed by Adobe Systems as a RAW image archival format and is supported by many image viewing and photo editing programs.
	
DOC	"Word processing document created by Microsoft Word, a word processor included with all versions of Microsoft Office; may contain formatted text, images, tables, graphs, charts, page formatting, and print settings."
	
DOCX	"Document created by Microsoft Word, a common word processing program; contains document text, images, formatting, styles, drawn objects, and other document settings; commonly used to author documents in business and academic settings."
	
DOT	"Template created by Microsoft Word, a word processing application; contains pre-formatted document settings, such as headers, footers, margins, font sizes, and other common page styles; used to create multiple documents that have similar formatting, such as company letterheads, business memos, or envelopes."
	
DOTX	"Template file created by Microsoft Word, a word processing program; contains default layouts and settings for a document, including styles, AutoText, toolbars, and macros; used as a baseline to create multiple .DOCX documents with the same formatting."
	
EML	"E-mail message saved by Microsoft Outlook or other e-mail programs; may also contain an e-mail attachment, or file sent with the message."
	
ERF	"Game archive used by the BioWare's game engine technologies, such as the Aurora Engine and Eclipse Engine; may contain various types of data for a game, including models, textures, animations, audio, and game levels; used for packaging original game content as well as for creating modifications and add-ons to the game."
	
FLAC	"Open-source audio format that uses lossless audio compression, meaning it does not remove any of the original audio data; compresses audio files with no loss in quality."
	
FLV	"Flash-compatible video file exported by the Flash Video Exporter plug-in (included with Adobe Flash) or other program with FLV file support; consists of a short header, interleaved audio, video, and metadata packets; audio and video data is stored in a similar format used by standard Flash (.SWF) files."
	
GIF	"Image file that may contain up to 256 indexed colors; color palette may be a predefined set of colors or may be adapted to the colors in the image; lossless format, meaning the clarity of the image is not compromised with GIF compression."
	
	"GIFs are common format for Web graphics, especially small images and images that contain text, such as navigation buttons. However, JPEG (.JPG) images are better for showing photos because they are not limited in the number of colors they can display."
	
GZ	Archive file compressed by the standard GNU zip (gzip) compression algorithm; contains a compressed collection of one or more files; commonly used on Unix operating systems for file compression.
	
	"Gzip is standardly installed on most Unix operating systems and is recognized by most file decompression utilities for Mac, Windows, and Unix. Gzip compression, while similar to .ZIP files, should not be confused with ZIP compression."
	
HTM	HTML Web page used by Web browsers; contains markup code that is stored a plain text format; used to display and format text and images in a Web browser.
	
	"HTM files serve the exact same purpose as .HTML files. The "".htm"" extension arose with the use of Microsoft Web development software, such as FrontPage, SharePoint Designer, and Expression Web."
	
HTML	"Web page coded in HTML that can be displayed in a Web browser; formats text, tables, images, and other content that is displayed on the page; most pages within static websites have an "".html"" extension."
	
	"The HTML source code is parsed by the Web browser and is typically not seen by the user. If you want to view the HTML of a Web page, select ""View Source"" from the Web browser's View menu. Since HTML files are saved in a standard text format, they can be opened and edited with a basic text editor."
	
ICA	Independent Computing Architecture (ICA) file used by Citrix application servers; contains configuration information for connecting to different servers; may link to a published application or to a server desktop environment.
	
	"ICA files allow users to connect to remote virtual desktops so the user's computer does not need the applications to be installed locally. This mechanism provides advantages for system administration and also allows users to access critical business applications, or ""enterprise applications,"" from remote locations."
	
	ICA files can be created with the ICA File Creator program or a basic text editor.
	
ICO	"Image format used for storing icons for Windows programs, files, and folders; contains two bitmaps: 1) the AND bitmap - the image mask (which determines what part of the icon is transparent) and 2) the XOR bitmap - contains the icon which is mapped onto the image mask; ICO files can be modified to create custom icons."
	
INI	Configuration file used by Windows programs to initialize program settings; contains sections for settings and preferences (delimited by a string in square brackets) with each section containing one or more name and value parameters.
	
JAR	"Java Archive (JAR) file used by the Java Runtime Environment (JRE), a framework used for executing Java programs; can contain .CLASS files, application resources, and an optional manifest file (META-INF/MANIFEST.MF); may serve as a program library or as a standalone program that runs if the JRE is installed on the computer."
	
JAVA	"Program written in the Java programming language, developed by Sun Microsystems (now Oracle); uses an object-oriented approach, where data types are defined as objects; may contain the entire code for a single program or may be one of many source code files referenced by a Java development project."
	
JPEG	"Compressed graphic format standardized by the Joint Photographic Experts Group (JPEG); supports up to 24-bit color, which makes JPEG a good format for storing digital photos; compressed using lossy compression, which may noticeably reduce the image quality if high amounts of compression are used."
	
	JPEG images are commonly used for Web graphics and for storing photos taken with digital cameras. They are usually saved with a .JPG extension.
	
JPG	"Compressed image format standardized by the Joint Photographic Experts Group (JPEG); commonly used for storing digital photos since the format supports up to 24-bit color; therefore, most digital cameras save images as JPG files by default."
	
	"JPEG is also a common format for publishing Web graphics since the JPEG compression algorithm significantly reduces the file size of images. However, the lossy compression used by JPEG may noticeably reduce the image quality if high amounts of compression are used."
	
JS	"Text file containing JavaScript code; used to execute JavaScript instructions in Web pages; may include functions that open and close windows, validate form fields, enable rollover images, or create drop-down menus."
	
JSP	"Server-generated Web page similar to an .ASP or .PHP file, but contains Java code instead of ActiveX or PHP; the code is parsed by the Web server, which generates HTML that is sent to the user's computer."
	
	"Since the Java code is parsed on the Web server, the end user never sees the JSP code, but only the HTML generated by the Java code in the page. JSP pages can be edited using a Web development program or basic text editor."
	
KML	"Stores geographic modeling information in XML format; includes points, lines, polygons, and images; used to identify and label locations, create different camera angles, overlay textures, and add HTML content."
	
	"KML files were originally used by Keyhole mapping software developed by Keyhole, Inc. The company was acquired by Google in 2004 and KML files are now used by used by Google Earth and other Earth browser programs."
	
LOG	Log file used by various operating systems and programs; typically contains a plain text log of certain events with their timestamps; may be created by the operating system to keep track of system events or by a software installation program to list location and names of installed files.
	
	"Web servers also generate log files to track visitors and to monitor bandwidth usage. Web stats programs allow Web hosts to analyze log files through generated charts and graphs, which present logged website traffic data in a graphical format."
	
MEF	Camera RAW image captured by a Mamiya digital camera; stores the image as it was captured by the camera's CCD; usually stored on a memory card and then transferred to the computer for editing and publishing.
	
MID	"Standard MIDI (Musical Instrument Digital Interface) file used by music authoring and mixing programs as well as MIDI hardware devices; contains music data, such as what notes are played, when they are played, how long each note is held, and how loud each note is played."
	
	"MID files are used to encode MIDI data into a standard format that is interoperable between different types of software programs and hardware devices. They may also contain controller data for a device. For example, a MID file can be used to change instruments on a MIDI hardware device or modify sustain pedal information."
	
	MID files contain attributes of music data rather than music data itself. They can be played back using software instruments that interpret this data.
	
MKV	"Video container format similar to the .AVI, .ASF, and .MOV formats; supports several types of audio and video codecs; may also include .SRT, .SSA, or USF (Universal Subtitle Format) subtitles and supports VobSub subtitles from DVDs."
	
	The Matroska video format has become popular in the anime fan-subbing community (where users create subtitles) since it supports multiple audio and subtitle tracks in the same file.
	
	"DivX Player supports MKV files on both Mac and Windows systems. MKV files can also be played on Palm, Symbian, and Pocket PC mobile devices using the CorePlayer Mobile software."
	
MOV	Common multimedia format often used for saving movies and other video files; uses a proprietary compression algorithm developed by Apple Computer; compatible with both Macintosh and Windows platforms.
	
MP3	"Compressed audio format developed by the Moving Picture Experts Group; uses ""Layer 3"" audio compression; commonly used to store music files and audiobooks on a hard drive; may provide near-CD quality sound (stereo, 16-bit) in a file roughly 1/10 the size of a .WAV or .AIF file."
	
	"The quality of an MP3 file depends largely on the bit rate used for compression. Common bit rates are 128, 160, 192, and 256 kbps. Higher bit rates result in higher quality files that also require more disk space."
	
	"MP3 files are supported by most portable music players, such as the Apple iPod and Microsoft Zune. They can also be played on the Amazon Kindle. Symbian OS mobile phones can play MP3 files using the UltraMP3 program."
	
MP4	"Movie or video clip that uses MPEG-4 compression, a standard developed by the Moving Picture Experts Group (MPEG); commonly used for sharing video files on the Internet."
	
	"The MPEG-4 video format uses separate compression for audio and video tracks. Video is compressed with MPEG-4 video encoding. Audio is compressed using AAC compression, the same type of audio compression used in .AAC files."
	
	"MP4 files are supported by many video programs and various hardware devices, including the Microsoft Zune portable media player."
	
MPEG	Popular video format standardized by the Moving Picture Experts Group (MPEG); compressed using MPEG-1 or MPEG-2 compression; often used for creating movies that are distributed over the Internet.
	
	MPEG movies are typically saved with an .MPG extension.
	
MPG	Common digital video format standardized by the Moving Picture Experts Group (MPEG); typically incorporates MPEG-1 or MPEG-2 audio and video compression; often used for creating movies that are distributed on the Internet.
	
MRW	Raw image format used by Minolta Dimage digital cameras; stores data in an uncompressed format exactly as it was captured by the camera's sensor; settings like color temperature and exposure can be edited with software after the image is saved on a computer.
	
MSG	"Message created or saved within Microsoft Outlook; contains multiple e-mail fields, including the date, sender, recipient, subject, and message body; compatible with other programs that use Microsoft's Messaging Applications Programming Interface (MAPI)."
	
NEF	Raw photo captured by a Nikon digital camera; saved in an uncompressed format that stores data exactly as it was captured by the CCD; adjustments to settings such as exposure and white balance can be made with software once the image is saved to a computer.
	
ODT	"Text document created with Writer, the OpenOffice.org and StarOffice word processor; formatted using the OASIS OpenDocument XML-based standard."
	
	"OpenDocument text files can be opened and edited with any OpenOffice-compatible program, including NeoOffice (Mac), AbiWord (Mac & Windows), and KWord (Unix). They can also be imported into Google Docs, Google's Web-based word processor and spreadsheet application."
	
ORF	Unprocessed RAW photo taken with an Olympus digital camera; contains unprocessed image data captured by the camera's sensor; settings such as exposure and white balance can be modified after the picture is taken.
	
PAGES	"Document created by Apple Pages, a word processor and page layout program; may be a basic text document or a complex multi-page brochure; can include text, pictures, photos, tables, graphs, and charts; may be created from a blank page or built from a template."
	
PDF	Cross-platform document created by Adobe Acrobat or a program with the Acrobat plug-in; commonly used for e-mail attachments or for saving publications in a standard format for viewing on multiple computers; usually created from another document instead of from scratch.
	
	"PDF files may contain text, images, forms, annotations, outlines, and other data. They preserve fonts and formatting electronically across multiple platforms and appear the same on the screen as they will when printed on paper."
	
PEF	"Uncompressed RAW photograph taken with a Pentax digital camera; stores image information exactly how it was captured by the camera's sensor, with no compression or color adjustment."
	
PHP	"Web page that may contain PHP code; may include PHP functions that can process online forms, get the date and time, or access information from a database, such as MySQL database."
	
	"The PHP code within the Web page is processed (parsed) by a PHP engine on the Web server, which dynamically generates HTML. The HTML, which contains the Web page content, is then sent to the user's Web browser. Therefore, the user never sees the actual PHP code contained in the Web page, even when viewing the page source."
	
PNG	"Image file stored in the Portable Network Graphic (PNG) format; like a .GIF file, contains a bitmap of indexed colors under a lossless compression, but without copyright limitations; commonly used to store graphics for Web images."
	
	"The PNG format was created in response to limitations with the GIF format, primarily to increase color support and to provide an image format without a patent license. Additionally, while GIF images only support fully opaque or fully transparent pixels, PNG images may include an 8-bit transparency channel, which allows the image colors to fade from opaque to transparent."
	
PPS	"Slide show created with Microsoft PowerPoint, a common program for creating presentations; saved as a completed slide show, which can be viewed by either PowerPoint or PowerPoint Viewer; not editable like a .PPT file."
	
PPT	"Editable slide show created with Microsoft PowerPoint; often used for presentations or slideshows; may include formatted text, bullet points, images, movies, sound effects, and music; often built from one of many templates included with the PowerPoint software, but may also be created from scratch."
	
PPTX	"Presentation file created by Microsoft PowerPoint, a program used to create slide show presentations; contains a collection of slides, including their text, images, formatting, animations, drawn objects, and other media; commonly used in business meetings, marketing applications, and academic classroom settings."
	
	"In contrast to .PPT files, which store all presentation data in a single binary file, PPTX files are created using the Open XML format, which stores documents as a collection of separate files in a compressed zip package. The file types include XML document properties, images, macros, charts, and other media files."
	
PSD	"Image file created by Adobe Photoshop, a professional image-editing program; may include image layers, adjustment layers, layer masks, annotation notes, file information, keywords, and other Photoshop-specific elements."
	
QIF	ASCII text file generated by Quicken financial software; contains a user's financial accounts in a text format; used to transfer data between different Quicken data files or from a financial institution's website to Quicken software.
	
	"The QIF format was originally developed by Intuit, but it is now supported by several financial and accounting programs."
	
RAF	"Uncompressed RAW photograph taken with a Fuji digital camera, such as a high-end FinePix model; contains unprocessed image data; may also include a .JPG version of the same image within the file."
	
RAR	"File archive containing one or more files compressed with RAR compression; uses a higher compression ratio than typical ZIP compression; incorporates a proprietary compression algorithm that is now used by other compressors, including 7-Zip for its .7Z files; may be extracted using a variety of programs."
	
	"The RAR compressor can also create spanned, or multi-volume, archives, which are split across several compressed files. These files typically have file extensions from "".R00"" to "".R99,"" or they may all have the standard "".RAR"" extension."
	
	"The name ""RAR"" stands for ""Roshal ARchive,"" which was named after Eugene Roshal, the RAR compression algorithm developer."
	
RAW	"Image file generated by digital cameras such as some Panasonic and Leica cameras; contains uncompressed, raw image data; can be adjusted for exposure and white balance in software after saving the image to the computer; used for storing unaltered image data as captured by a digital camera's CCD."
	
	"RAW files may also be created by image generation software, although this is not as common."
	
REG	Windows Registry File
	
RESX	"Resource file used by programs developed with Microsoft's .NET Framework; stores objects and strings for a program in an XML format; may contain both plain text information as well as binary data, which is encoded as text within the XML tags."
	
	"RESX files are commonly used to store application settings and other program resources, such as pictures. If implemented correctly, they may be swapped out for other resource bundles without having to recompile the application again. This is useful when localizing programs to different environments."
	
RTF	"Common text file format that supports ""rich text;"" may include several types of text formatting, such as bold type, italics, different fonts and font sizes, custom tab settings, etc; may also support images saved within the text file."
	
SQL	"File written in SQL (Structured Query Language); contains SQL code used to modify the contents of a relational database; may contain statements for creating or modifying database structures, or may contain insertions, updates, deletions, and other SQL operations."
	
SR2	Digital photo captured by a Sony digital camera; contains a RAW image as captured by the camera's CCD; may be imported into image manipulation programs for touch-ups and other camera shooting corrections.
	
SRT	"Text file containing subtitles used by various video playback programs; supported by DivX, DVD, and other video formats; includes the time each subtitle should be displayed followed by the text of the subtitle."
	
	"Subtitle files are often named according to the language of the subtitles, i.e. ""moviename.eng.srt"" for English and ""moviename.ger.srt"" for German subtitles."
	
SVG	Two-dimensional vector graphic format created by the World Wide Web Consortium (W3C); developed as a standard format for displaying vector graphics on the Web; describes images using a text format that is based on XML.
	
SWF	Animation created with Adobe Flash; may contain text as well as both vector and raster graphics; also may include interactive actions written in ActionScript; plays in Web browsers that have the Flash plug-in installed.
	
TAR	"Tar archive created by tar, a Unix-based utility used to package files together; contains multiple files stored in an uncompressed format; commonly compressed into a .GZ file using GNU Zip compression."
	
TGZ	Unix .TAR file archive compressed with Gnu Zip (.GZIP) compression; the TAR file archives multiple files into one file and the Gzip compression reduces the archive file size.
	
TIF	"High-quality graphics format often used for storing images with many colors, such as digital photos; short for ""TIFF;"" includes support for layers and multiple pages."
	
	"TIFF files can be saved in an uncompressed (lossless) format or may incorporate .JPEG (lossy) compression. They may also use LZW lossless compression, which reduces the TIFF file size, but does not reduce the quality of the image."
	
TIFF	Graphics container that can store both raster and vector images; may contain high-quality graphics that support color depths from 1 to 24-bit; supports both lossy and lossless compression; also supports multiple layers and pages.
	
	TIFF files were designed to be a standard image format for saving high-quality color images on multiple computer platforms. They are most often seen with the .TIF extension.
	
TORRENT	"URL of a file or group of files downloadable with BitTorrent, a peer-to-peer (P2P) file sharing program; may be downloaded from multiple locations at one time; BitTorrent downloads are split among multiple nodes, which reduces the bandwidth used by the primary server and speeds up download times."
	
TXT	Standard text document that contains unformatted text; recognized by any text editing or word processing program; can also be processed by most other software programs.
	
VB	Virtual Basic script written in the VBScript scripting language; can be executed in Windows using the built-in scripting support; may run directly from the operating system or within Internet Explorer.
	
VCF	"Standard file format for storing contact information for a person or business; typically includes a name, address, phone number, e-mail address, and other contact information; also supports custom fields, images, and other types of media."
	
	"VCF files are often used for importing and exporting contacts from address books. They may be attached to e-mail messages, which provides the recipient with an easy way to import the sender's contact information."
	
WAV	"Standard digital audio file format used for storing waveform data; allows audio recordings to be saved with different sampling rates and bitrates; often saved in a 44.1 KHz, 16-bit, stereo format, which is the standard format used for CD audio."
	
WMV	Video file based on the Microsoft Advanced Systems Format (ASF) container format and compressed with Windows Media compression; basically an .ASF file that is encoded using the Windows Media Video (WMV) codec; Windows Media audio files are saved with a .WMA extension.
	
WPS	"Document created with Microsoft Works word processing software; similar to a Microsoft Word (.DOC) document, but does not include advanced formatting options and macros that a Word document may contain."
	
X3F	"RAW file saved in SIGMA's X3F format, a high-end digital photo format also known as the Foveon X3 format or ""FOVb;"" holds data for a single image captured with a digital camera; supports the image data, thumbnails, preview images, and text property information; can be edited with several photo-editing applications."
	
XFDL	"Extensible Forms Description Language (XFDL) file that uses XML to describe a structured, legally-binding business form; contains business form data including layout, business transaction details, inline mathematical and conditional expressions, and digital signatures; addresses business transaction needs for non-repudiation, auditability, security, and preservation of context."
	
	XFDL files were designed to create standardized and interchangeable business forms. They were adapted from the Universal Forms Description Language (UDFL) to include the XML format. They are used in business and government e-Commerce transactions.
	
XLS	"Spreadsheet created by Microsoft Excel, the most widely-used spreadsheet program; stores data in a table with rows and columns; table cells may contain manually entered data or the results computed from the data of other cells; often used to create charts and graphs."
	
XLSM	"Macro-enabled spreadsheet created by Microsoft Excel, a spreadsheet program; contains worksheets of cells arranged by rows and columns as well as embedded macros programmed in the Visual Basic for Applications (VBA) language; saved in the Open XML format introduced in Microsoft Office 2007."
	
	"XLSM files are .XLSX files, but with macros enabled. They may be opened with Excel 2007 or later, or by previous versions of Excel with Open XML component support. For security reasons, Excel does not enable macros by default."
	
XLSX	"Spreadsheet created with Microsoft Excel, a program used to create spreadsheets; stores data in worksheets, which contain cells arranged in a grid of rows and columns; may also contain charts, mathematical functions, styles, and formatting; commonly used to store financial data and to create simple or complex mathematical models."
	
	"Each cell in an XLSX spreadsheet may be formatted individually. For example, cells may have a number, text, currency, or other format as well as color, border style, custom font, and size. Cells may reference other cells to compute a resulting value"
	
XML	"XML (Extensible Markup Language) data file that uses tags to define objects and object attributes; formatted much like an .HTML document, but uses custom tags to define objects and the data within each object; can be thought of as a text-based database."
	
	"XML files have become a standard way of storing and transferring data between programs and over the Internet. Because they are formatted as text documents, they can be edited by a basic text editor."
	
XPI	"Compressed installation archive used by various Mozilla applications, including Firefox, Thunderbird, and SeaMonkey; may contain the primary components installed with the software, or may contain an software extension, such as a Web-browser plug-in."
	
	"XPI files can often be installed by simply dragging and dropping the file onto an open Web browser window. They are installed by Mozilla installer script, which is part of the XPInstall component included with the software."
	
XPS	"Descriptor file containing information written in the XPS page description language developed by Microsoft; formatted like an .XML file and can define the layout, appearance, and printing information for a document."
	
	"XPS was designed as a replacement for the Enhanced Metafile (.EMF) format. It is similar to a .PDF file, but is based on XML instead of the PostScript language. XPS files can be created in Windows by selecting the ""Microsoft XPS Document Writer"" as the printer when printing a document."
	
ZIP	"File compressed or ""zipped"" using Zip compression, a common type of compression in which every file in the archive is compressed separately; supported by most file compression/decompression programs."

DLL	"Compiled library file containing a set of procedures and/or drivers that are referenced and executed by a program; allows multiple programs to access shared system functions through common libraries; may be dynamically linked into a program at runtime. Many DLL files are provided with the Windows operating system, and others are included by Windows programs. They allow various program functions, such as communication with external devices and hard disk input and output. They may also be referenced by Mac cross-platform applications."

EXE	"Executable program file created for Windows or DOS operating systems; runs when opened and should execute when double-clicked; can also be a self-extracting archive that extracts files to a specified location."
