Access (Microsoft Access)
A database system developed by Microsoft. Part of Microsoft Office Professional. Mostly used on low traffic web sites running on the Windows platform.

ActiveMovie
A web technology for streaming movies from a web server to a web client. Developed by Microsoft.

ActiveX
A programming interface (API) that allows web browsers to download and execute Windows programs. (See also Plug-In)

Address
See Web Address.

Anchor
In web terms: The starting point or ending point of a hyperlink.

Anonymous FTP
See FTP Server.

ANSI (American National Standards Institute)
An organization that creates standards for the computer industry. Responsible for the ANSI C standard.

ANSI C
An international standard for the C programming language.

ADO (ActiveX Data Object)
A Microsoft technology that provides data access to any kind of data store.

ADSL (Asymmetric Digital Subscriber Line)
A special type of DSL line where the upload speed is different from the download speed.

Amaya
An open source web browser editor from W3C, used to push leading-edge ideas in browser design.

Animation
A set of pictures simulating movement when played in series.

Anti-Virus Program
A computer program made to discover and destroy all types of computer viruses.

Apache
An open source web server. Mostly for Unix, Linux and Solaris platforms.

Applet
See web applet.

Archie
A computer program to locate files on public FTP servers.

API (Application Programming Interface)
An interface for letting a program communicate with another program. In web terms: An interface for letting web browsers or web servers communicate with other programs. (See also Active-X and Plug-In)

ARPAnet
The experimental network tested in the 1970's which started the development of the Internet.

Authentication
In web terms: the method used to verify the identity of a user, program or computer on the web.

ASCII (American Standard Code for Information Interchange)
A set of 128 alphanumeric and special control characters used for computer storing and printing of text. Used by HTML when transmitting data over the web.

ASF (Advanced Streaming Format)
A multimedia streaming format. Developed by Microsoft for Windows Media.

ASP (Active Server Pages)
A Microsoft technology allowing the insertion of server executable scripts in web pages.

ASX (ASF Streaming Redirector)
An XML format for storing information about ASF files. Developed by Microsoft for Windows Media.

AVI (Audio Video Interleave)
File format for video files. Video compression technology developed by Microsoft.

Banner Ad
A (most often graphic) advertisement placed on a web page, which acts as a hyperlink to an advertiser's web site.

Bandwidth
A measure for the speed (amount of data) you can send through an Internet connection. The more bandwidth, the faster the connection.

Baud
The number of symbols per second sent over a channel.

BBS (Bulletin Board System)
A web based public system for sharing discussions, files, and announcements.

Binary Data
Data in machine readable form.

Bit (Binary Digit)
The smallest unit of data stored in a computer. A bit can have the value of 0 or 1. A computer uses 8 bits to store one text character.

BMP (Bitmap)
A format for storing images.

Bookmark
In web terms: A link to a particular web site, stored (bookmarked) by a web user for future use and easy access.

Browse
Term to describe a user's movement across the web, moving from page to page via hyperlinks, using a web browser. (See Web Browser).

BPS (Bits Per Second)
Term to describe the transmission speed for data over the web.

Browser
See Web Browser.

Byte (Binary Term)
A computer storage unit containing 8 bits. Each byte can store one text character.

C
An advanced programming language used for programming advanced computer applications.

C++ (C Plus Plus)
The same as C with added object-oriented functions.

C# (C Sharp)
A Microsoft version of C++ with added Java-like functions.

Case Sensitive
A term used to describe if it is of importance to use upper or lower case letters.

Cache
In web terms: A web browser or web server feature which stores copies of web pages on a computer's hard disk.

Chat
An on-line text-based communication between Internet users.

CGI (Common Gateway Interface)
A set of rules that describes how a CGI program communicates with a web server.

CGI Bin
The folder (or directory) on a web server that stores CGI programs.

CGI Program
A small program that handles input and output from a web server. Often CGI programs are used for handling forms input or database queries.

Cinepac
A codec for computer video.

Client
See Web Client.

Client/Server
In web terms: The communication and separation of workload between a web client and a web server.

Click
In web terms: A mouse click on a hyperlink element (such as text or picture) on a web page which creates an event such as taking a visitor to another web page or another part of the same page.

Clickthrough Rate
The number of times visitors click on a hyperlink (or advertisement) on a page, as a percentage of the number of times the page has been displayed.

Codec (Compressor / Decompressor)
Common term for the technology used for compressing and decompressing data.

Communication Protocol
A standard (language and a set of rules) to allow computers to interact in a standard way. Examples are IP, FTP, and HTTP.

Compression
A method of reducing the size (compress) of web documents or graphics for faster delivery via the web.

Computer Virus
A computer program that can harm a computer by displaying messages, deleting files, or even destroying the computer's operating system.

Cookie
Information from a web server, stored on your computer by your web browser. The purpose of a cookie is to provide information about your visit to the website for use by the server during a later visit.

ColdFusion
Web development software for most platforms (Linux, Unix, Solaris and Windows).

CSS (Cascading Style Sheets)
A W3C recommended language for defining style (such as font, size, color, spacing, etc.) for web documents.

Database
Data stored in a computer in such a way that a computer program can easily retrieve and manipulate the data.

Database System
A computer program (like MS Access, Oracle, and MySQL) for manipulating data in a database.

DB2
A database system from IBM. Mostly for Unix and Solaris platforms.

DBA (Data Base Administrator)
The person (or the software) who administers a database. Typical task are: backup, maintenance and implementation.

DHCP (Dynamic Host Configuration Protocol)
An Internet standard protocol that assigns new IP addresses to users as need.

DHTML (Dynamic HTML)
A term commonly to describe HTML content that can change dynamically.

Dial-up Connection
In web terms: A connection to Internet via telephone and modem.

Discussion Group
See Newsgroup.

DNS (Domain Name Service)
A computer program running on a web server, translating domain names into IP addresses.

DNS Server
A web server running DNS.

DOM (Document Object Model)
A programming model for web page objects. (See HTML DOM and XML DOM)

Domain Name
The name that identifies a web site. (like: W3Schools.com)

DOS (Disk Operating System)
A general disk based computer operating system (see OS). Originally developed by Microsoft for IBM personal computers. Often used as a shorthand for MS-DOS.

Download
To transfer a file from a remote computer to a local computer. In web terms: to transfer a file from a web server to a web client. (see also Upload).

DSL (Digital Subscriber Line)
An Internet connection over regular telephone lines, but much faster. Speed may vary from 128 kilobit per second, up to 9 megabit per second.

DTD (Document Type Definition)
A set of rules (a language) for defining the legal building blocks of a web document like HTML or XML.

Dynamic IP
An IP address that changes each time you connect to the Internet. (See DHCP and Static IP).

E-mail (Electronic Mail)
Messages sent from one person to another via the Internet.

E-mail Address
The address used for sending e-mails to a person or an organization. Typical format is username@hostname.

E-mail Server
A web server dedicated to the task of serving e-mail.

Encryption
To convert data from its original form to a form that can only be read by someone that can reverse the encryption. The purpose of encryption is to prevent unauthorized reading of the data.

Error
See Web Server Error.

Ethernet
A type of local area network (see LAN).

Firewall
Software that acts as a security filter that can restrict types of network communication. Most often used between an individual computer (or a LAN) and the Internet.

Flash
A vector-based multimedia format developed by Macromedia for use on the web.

Form
See HTML Form.

Forum
In web terms: The same as Newsgroup.

Frame
In web terms: A part of the browser screen displaying a particular content. Frames are often used to display content from different web pages.

FrontPage
Web development software for the Windows platform. Developed by Microsoft.

FTP (File Transfer Protocol)
One of the most common methods for sending files between two computers.

FTP Server
A web server you can logon to, and download files from (or upload files to). Anonymous FTP is a method for downloading files from an FTP server without using a logon account.

Gateway
A computer program for transferring (and reformatting) data between incompatible applications or networks.

GIF (Graphics Interchange Format)
A compressed format for storing images developed by CompuServe. One of the most common image formats on the Internet.

GB
Same as Gigabyte. 10GB is ten gigabytes.

Gigabyte
1024 megabytes. Commonly rounded down to one billion bytes.

Graphics
In web terms graphics describe pictures (opposite to text).

Graphic Monitor
A display monitor that can display graphics.

Graphic Printer
A printer that can print graphics.

Graphical Banner
See Banner Ad.

Helper application
In web terms: A program helping the browser to display, view, or work with files that the browser cannot handle itself. (See Plug-In).

Hits
The number of times a web object (page or picture) has been viewed or downloaded. (See also Page Hits).

Home Page
The top-level (main) page of a web site. The default page displayed when you visit a web site.

Host
See Web Host.

Hosting
See Web Hosting.

Hotlink
See Hyperlink.

Trojan Horse
Computer program hidden in another computer program with the purpose of  destroying software or collecting information about the use of the computer.

HTML (Hypertext Markup Language)
HTML is the language of the web. HTML is a set of tags that are used to define the content, layout and the formatting of the web document. Web browsers use the HTML tags to define how to display the text.

HTML Document
A document written in HTML.

HTML DOM (HTML Document Object Model)
A programming interface for HTML documents.

HTML Editor
A software program for editing HTML pages. With an HTML editor you can add elements like lists, tables, layout, font size, and colors to a HTML document like using a word processor. An HTML editor will display the page being edited exactly the same way it will be displayed on the web (See WYSIWYG).

HTML Form
A form that passes user input back to the server.

HTML Page
The same as an HTML Document.

HTML Tags
Code to identify the different parts of a document so that a web browser will know how to display it.

HTTP (Hyper Text Transfer Protocol)
The standard set of rules for sending text files across the Internet. It requires an HTTP client program at one end, and an HTTP server program at the other end.

HTTP Client
A computer program that requests a service from a web server.

HTTP Server
A computer program providing services from a web server.

HTTPS (Hyper Text Transfer Protocol Secure)
Same as HTTP but provides secure Internet communication using SSL. (see also SSL)

Hyperlink
A pointer to another document. Most often a pointer to another web page. A hyperlink is a synonym for a hotlink or a link, and sometimes called a hypertext connection to another document or web page.

Hypermedia
An extension to hypertext to include graphics and audio.

Hypertext
Hypertext is text that is cross-linked to other documents in such a way that the reader can read related documents by clicking on a highlighted word or symbol. (see also hyperlink)

IAB (Internet Architecture Board)
A council that makes decisions about Internet standards. (See also W3C).

IE (Internet Explorer)
See Internet Explorer.

IETF (Internet Engineering Task Force)
A subgroup of IAB that focuses on solving technical problems on the Internet.

IIS (Internet Information Server)
A web server for Windows operating systems. Developed by Microsoft.

IMAP (Internet Message Access Protocol)
A standard communication protocol for retrieving e-mails from an e-mail server. IMAP is much like POP but more advanced.

Indeo
A codec for computer video developed by Intel.

Internet
A world wide network connecting millions of computers. (See also WWW)

Internet Browser
See Web Browser.

Internet Explorer
A browser by Microsoft. The most commonly used browser today.

Internet Server
See Web Server

Intranet
A private (closed) Internet, running inside a LAN (Local Area Network).

IP (Internet Protocol)
See TCP/IP.

IP Address (Internet Protocol Address)
A unique number identifying every computer on the Internet (like 197.123.22.240)

IP Number (Internet Protocol Number)
Same as an IP address.

IP Packet
See TCP/IP Packet.

IRC (Internet Relay Chat)
An Internet system that enables users to take part in on-line discussions.

IRC Client
A computer program that enables a user to connect to IRC.

IRC Server
An Internet server dedicated to the task of serving IRC connections.

ISAPI (Internet Server API)
Application Programming Interface (See API) for Internet Information Server (See IIS).

ISDN (Integrated Services Digital Network)
A telecommunication standard that uses digital transmission to support data communications over regular telephone lines.

ISP (Internet Service Provider)
Someone that provides access to the Internet and web hosting.

Java
A programming language developed by SUN. Mostly for programming web servers and web applets. 

Java Applet
See Web Applet.

JavaScript
The most popular scripting language on the internet, developed by Netscape.

JPEG (Joint Photographic Expert Group)
The organization that promotes the JPG and JPEG graphic formats for storing compressed images. 

JPEG and JPG
Graphic formats for storing compressed images. 

JScript
Microsoft's version of JavaScript.

JSP (Java Server Pages)
A Java based technology allowing the insertion of server executable scripts in web pages. Mostly used on Linux, Unix and Solaris platforms. 

K
Same as kilobyte 10K is ten kilobytes..

KB
Same as kilobyte 10KB is ten kilobytes..

Keyword
In web terms: A word used by a search engine to search for relevant web information.
In database terms: A word (or index) used to identify a database record.

Kilobyte
1024 bytes. Often called 1K, and rounded down to 1000 bytes.

LAN (Local Area Network)
A network between computers in a local area (like inside a building), usually connected via local cables. See also WAN.

Link
The same as a hyperlink.

Linux
Open source computer operating system based on Unix. Mostly used on servers and web servers.

Mail
In web terms: the same as e-mail.

Mail Server
See e-mail server.

MB
Same as Megabyte. 10MB is ten megabytes.

Megabyte
1024 kilobytes. Commonly rounded down to one million bytes.

Meta Data
Data that describes other data. (See also Meta Tags).

Meta Search
The method of searching for meta data in documents.

Meta Tags
Tags inserted into documents to describe the document.

MIDI (Musical Instrument Digital Interface)
A standard protocol for communication between computers and musical instruments.

MIME (Multipurpose Internet Mail Extensions)
An Internet standard for defining document types. MIME type examples: text/plain, text/html, image/gif, image/jpg.

MIME Types
Document types defined by MIME.

Modem
Hardware equipment to connect a computer to a telephone network Typically used to connect to the Internet via a telephone line.

Mosaic
The first commonly available web browser. Mosaic was released in 1993 and started the popularity of the web.

MOV
A codec for computer video developed by Apple. Common file extension for QuickTime multimedia files.

MP3 (MPEG-1 Audio Layer-3)
An audio compression format specially designed for easy download over the Internet.

MP3 File
An file containing audio compressed with MP3. Most often a music track.

MPEG (Moving Picture Expert Group)
An ISO standard codec for computer audio and video.

MPG
Common file extension for MPEG files.

MS-DOS (Microsoft Disk Operating System)
A general disk based computer operating system (See OS). Originally developed by Microsoft for IBM computers, then developed by Microsoft as a basis for the first versions of Windows.

Multimedia
In web terms: A presentation combining text with pictures, video, or sound.

MySQL
Free open source database software often used on the web.

NetBEUI (Net Bios Extended User Interface)
An enhanced version of NetBIOS.

NetBIOS (Network Basic Input Output System)
An application programming interface (API) with functions for local-area networks (LAN). Used by DOS and Windows.

Navigate
In web terms: The same as Browse.

Netscape
The browser from the company Netscape. The most popular browser for many years. Today IE has the lead.

Newsgroup
An on-line discussion group (a section on a news server) dedicated to a particular subject of interest.

News Reader
A computer program that enables you to read (and post messages) from an Internet newsgroup.

News Server
An Internet server dedicated to the task of serving Internet newsgroups.

Node
In web terms: A computer connected to the Internet, most often used to describe a web server.

Opera
The browser from the company Opera.

OS (Operating System)
The software that manages the basic operating of a computer.

Packet
See TCP/IP Packet.

Page Hits
The number of times a web page has been visited by a user.

Page Impressions
The same as Page Hits.

Page Views
The same as Page Hits.

PDF (Portable Document Format)
A document file format developed by Adobe. Most often used for text documents.

Perl (Practical Extraction and Reporting Language)
A scripting language for web servers. Most often used on Unix servers.

PHP (PHP: Hypertext Preprocessor)
A technology allowing the insertion of server executable scripts in web pages. Mostly for Unix, Linux and Solaris platforms.

Ping
A method used to check the communication between two computers. A "ping" is sent to a remote computer to see if it responds.

Platform
In web terms: The computer's operating system like Windows, Linux, or OS X.

Plug-In
An application built into another application. In web terms: A program built in (or added) to a web browser to handle a special type of data like e-mail, sound, or movie files. (See also ActiveX)

PNG (Portable Network Graphics)
A format for encoding a picture pixel by pixel and sending it over the web. A W3C recommendation for replacing GIF.

POP (Post Office Protocol)
A standard communication protocol for retrieving e-mails from an e-mail server. (See also IMAP).

Port
A number that identifies a computer IO (input/output) channel. In web terms: A number that identifies the I/O channel used by an Internet application (A web server normally uses port 80).

Protocol
See Communication Protocol.

PPP (Point to Point Protocol)
A communication protocol used for direct connection between two computers.

Proxy Server
An Internet server dedicated to improve Internet performance.

Router
A hardware (or software) system that directs (routes) data transfer to different computers in a network.

QuickTime
A multimedia file format created by Apple.

RAID (Redundant Array of Independent Disks)
A standard for connecting multiple disks to the same server for higher security, speed and performance. Often used on web servers.

RDF (Resource Description Framework)
A framework for constructing languages for describing web resources.

Real Audio
A common multimedia audio format created by Real Networks.

Real Video
A common multimedia video format created by Real Networks.

Redirect
In web terms: The action when a web page automatically forwards (redirects) the user to another web page.

RGB (Red Green Blue)
The combination of the three primary colors that can represent a full color spectrum.

Robot
See Web Robot.

Schema
See XML Schema.

Script
A collection of statements written in a Scripting Language.

Scripting Language
In web terms: A simple programming language that can be executed by a web browser or a web server. See JavaScript and VBScript.

Scripting
Writing a script.

Shareware
Software that you can try free of charge, and pay a fee to continue to use legally.

Shockwave
A format (technology) developed by Macromedia for embedding multimedia content in web pages.

Search Engine
Computer program used to search and catalog (index) the millions of pages of available information on the web. Common search engines are Google and AltaVista.

Semantic Web
A web of data with a meaning in the sense that computer programs can know enough about the data to process it.

Server
See Web Server.

Server Errors
See Web Server Errors.

SGML (Standard Generalized Markup Language)
An international standard for markup languages. The basis for HTML and XML.

SMIL (Synchronized Multimedia Integration Language)
A W3C recommended language for creating multimedia presentations.

SMTP (Simple Mail Transfer Protocol)
A standard communication protocol for sending e-mail messages between computers.

SOAP (Simple Object Access Protocol)
A standard protocol for letting applications communicate with each other using XML.

Solaris
Computer operating system from SUN.

SPAM
In web terms: The action of sending multiple unwelcome messages to a newsgroup or mailing list.

Spider
See Web Spider.

Spoofing
Addressing a web page or an e-mail with a false referrer. Like sending an e-mail from a false address.

Spyware
Computer software hidden in a computer with the purpose of collecting information about the use of the computer.

SQL (Structured Query Language)
An ANSI standard computer language for accessing and manipulating databases.

SQL Server
A database system from Microsoft. Mostly used on high traffic web sites running on the Windows platform.

SSI (Server Side Include)
A type of HTML comment inserted into a web page to instruct the web server to generate dynamic content. The most common use is to include standard header or footer for the page.

SSL (Secure Socket Layer)
Software to secure and protect web site communication using encrypted transmission of data.

Static IP (address)
An IP address that is the same each time connect to the Internet. (See also Dynamic IP).

Streaming
A method of sending audio and video files over the Internet in such a way that the user can view the file while it is being transferred.

Streaming Format
The format used for files being streamed over the Internet. (See Windows Media, Real Video and QuickTime).

SVG (Scalable Vector Graphics)
A W3C recommended language for defining graphics in XML.

Tag
In web terms: Notifications or commands written into a web document. (See HTML Tags)

TCP (Transmission Control Protocol)
See TCP/IP.

TCP/IP (Transmission Control Protocol / Internet Protocol)
A collection of Internet communication protocols between two computers. The TCP protocol is responsible for an error free connection between two computers, while the IP protocol is responsible for the data packets sent over the network.

TCP/IP Address
See IP Address.

TCP/IP Packet
A "packet" of data sent over a TCP/IP network. (data sent over the Internet is broken down into small "packets" from 40 to 32000 bytes long).

UDDI (Universal Description Discovery and Integration)
A platform-independent framework for describing services, discovering businesses, and integrating business services using the Internet.

Unix
Computer operating system, developed by Bell Laboratories. Mostly used for servers and web servers.

UNZIP
To uncompress a ZIPPED file. See ZIP.

Upload
To transfer a file from a local computer to a remote computer. In web terms: to transfer a file from a web client to a web server. (see also Download).

URI (Uniform Resource Identifier)
Term used to identify resources on the internet. URL is one type of an URI.

URL (Uniform Resource Locator)
A web address. The standard way to address web documents (pages) on the Internet (like: http://www.w3schools.com/)

USENET
A world wide news system accessible over the Internet. (See Newsgroups)

User Agent
The same as a Web Browser.

VB (Visual Basic)
See Visual Basic.

VBScript
A scripting language from Microsoft. VBScript is the default scripting language in ASP. Can also be used to program Internet Explorer.

Virus
Same as Computer Virus.

Visit
In web terms: A visit to a web site. Commonly used to describe the activity for one visitor of a web site.

Visitor
In web terms: A visitor of a web site. Commonly used to describe a person visiting (viewing) a web site.

Visual Basic
A programming language from Microsoft.

VPN (Virtual Private Network)
A private network between two remote sites, over a secure encrypted virtual Internet connection (a tunnel).

VRML (Virtual Reality Modeling Language)
A programming language to allow 3D effects to be added to HTML documents.

W3C (World Wide Web Consortium)
The organization responsible for managing standards for the WWW.

WAN (Wide Area Network)
Computers connected together in a wide network, larger than a LAN, usually connected via phone lines. See also LAN.

WAP (Wireless Application Protocol)
A leading standard for information services on wireless terminals like digital mobile phones.

Web Address
The same as an URL or URI. See URL.

Web Applet
A program that can be downloaded over the web and run on the user's computer. Most often written in Java.

Web Client
A software program used to access web pages. Sometimes the same as a Web Browser, but often used as a broader term.

Web Browser
A software program used to display web pages.

Web Document
A document formatted for distribution over the web. Most often a web document is formatted in a markup language like HTML or XML.

Web Error
See Web Server Error.

Web Form
See HTML Form.

Web Host
A web server that "hosts" web services like providing web site space to companies or individuals.

Web Hosting
The action of providing web host services.

Web Page
A document (normally an HTML file) designed to be distributed over the Web.

Web Robot
See Web Spider.

Web Server
A server is a computer that delivers services or information to other computers. In web terms: A server that delivers web content to web browsers.

Web Server Error
A message from a web server indicating an error. The most common web server error is "404 File Not Found".

Web Services
Software components and applications running on web servers. The server provides these services to other computers, browsers or individuals, using standard communication protocols.

Web Site
A collection of related web pages belonging to a company or an individual.

Web Spider
A computer program that searches the Internet for web pages. Common web spiders are the one used by search engines like Google and AltaVista to index the web. Web spiders are also called web robots or wanderers.

Web Wanderer
See Web Spider.

Wildcard
A character used to substitute any character(s). Most often used as an asterix (*) in search tools.

Windows 2000, Windows NT, Windows 95/98, Windows XP
Computer operating systems from Microsoft.

Windows Media
Audio and video formats for the Internet, developed by Microsoft. (See ASF, ASX, WMA and WMF).

WINZIP
A computer program for compressing and decompressing files. See ZIP.

WMA
Audio file format for the Internet, developed by Microsoft. (See also WMV).

WMV
Video file format for the Internet, developed by Microsoft. (See also WMA).

WML (Wireless Markup Language)
A standard for information services on wireless terminals like digital mobile phones, inherited from HTML, but based on XML, and much stricter than HTML.

WML Script
Scripting language (programming language) for WML.

Worm
A computer virus that can make copies of itself and spread to other computers over the Internet.

WSDL (Web Services Description Language)
An XML-based language for describing Web services and how to access them.

WWW (World Wide Web)
A global network of computers using the internet to exchange web documents. (See also Internet)

WWW Server
The same as a Web Server.

WYSIWYG (What You See Is What You Get)
In Web terms: To display a web page being edited exactly the same way it will be displayed on the web.

XForms
A future version of HTML Forms, based on XML and XHTML. Differs from HTML forms by separating data definition and data display. Providing richer and more device independent user input.

XHTML (Extensible Hypertext Markup Language)
HTML reformulated as XML. XHTML is the latest version of HTML. Developed by W3C.

XPath
XPath is a set of syntax rules (language) for defining parts of an XML document. XPath is a major part of the W3C XSL standard.

XQuery
XQuery is a set of syntax rules (language) for extracting information from XML documents. XQuery builds on XPath. XQuery is developed by W3C.

XML (Extensible Markup Language)
A simplified version of SGML especially designed for web documents, developed by the W3C.

XML Document
A document written in XML.

XML DOM (XML Document Object Model)
A programming interface for XML documents developed by W3C.

XML Schema
A document that describes, in a formal way, the syntax elements and parameters of a web language. Designed by W3C to replace DTD.

XSD (XML Schema Definition)
The same as XML Schema.

XSL (Extensible Stylesheet Language)
A suite of XML languages developed by W3C, including XSLT, XSL-FO and XPath.

XSL-FO (XSL Formatting Objects)
An XML language for formatting XML documents. A part of XSL developed by W3C.

XSLT (XSL Transformations)
An XML language for transforming XML documents. A part of XSL developed by W3C.

ZIP
A compressing format for computer files. Commonly used for compressing files before downloading over the Internet. ZIP files can be compressed (ZIPPED) and decompressed (UNZIPPED) using a computer program like WINZIP.