Email        Short for electronic mail, a system of sending notes and memos between computers via internet.

EMS        Enhanced Messaging Service. A development of SMS (Short Messaging Service) that allows simple pictures and ring tones to be sent between mobile phones

Emulate        An program that is used to make a computer act like another computer. For example, there are programs that can enable a PC to emulate a video arcade game.

Encoder        In the context of digital music, a piece of software that converts audio CDs to MP3 or some other digital format.

Encryption        The science of scrambling data  be it text, audio, or video so that it can only be read by the authorised sender and recipient. Encryption can also be used to embed identifying markings in data, so that it can't be undetectably falsified.

Ethernet        A type of computer network developed by Xerox in the 1970s, allowing a number of PCs to be linked together and communicate with one another.

Events        An action in Windows, such as opening a document, emptying the Recycle Bin, or shutting down your PC.

Expansion card        Card that can be fitted in an expansion slot within your PC to enhance its capabilities, for instance to improve its video or graphics performance.

Expansion slot        A socket on a computer's motherboard designed to accommodate expansion cards.

Explorer        A program supplied with Windows that's used to browse files on your PC. Explorer can be used an alternative to the Windows Desktop.

Extension        The three-letter code at the end of a filename that indicates the type or format of the file. For example,. BMP is a bitmap,. EXE is an executable program file. These enable Windows to recognise what type of file it's dealing with.

Extract        The process of expanding compressed files so they can be opened

FAQ        Stands for frequently asked questions, usually a text file containing useful information about an application or website.

FAT File Allocation Table        A system used by Windows to organise files stored on a hard disk. Windows 95 used a system called FAT16, Windows 98 and Me use FAT32 that allows, among other things, long filenames

Favorites/Bookmarks        Your personal address book of places on the internet that you visit periodically. Bookmark a site and it will be stored in your Favorites/Bookmarks list for future visits.

Feathering        A term used to describe a print-out of a text or picture which is marred by blurred or irregular edges.

Field        In a database, a field is an individual container that can hold a particular type of information. For example, if you have a contacts list of your customers, each entry is called a record and the various parts of each record are called fields.

File extension        The file extension is the suffix  or letters after the dot  in a file's name. Examples include .doc (for a word document) and .xls (Excel) and .txt (Notepad). This is how Windows knows which application to use to open a particular file.

File Manager        Part of the Windows 3. 1 operating system, since replaced in later versions of Windows by Explorer. File Manager displays lists of all of the files you have stored on your PC's hard disk.

Fill        The interior area of a vector shape, which may be given a colour, gradient, pattern, texture or a bitmap image.

Filter        In image-editing, applies a transformation to either improve image quality or produce special effect on all or part of an image. There is a filter for every need from sharpening out-of-focus pictures to wrapping them round spheres.

Firewall        A system that prevents unauthorised access to a computer over a network, such as the internet. Firewalls can be either hardware or software  businesses tend to use the former; home users the latter.

FireWire        A super-fast data link between your PC and devices such as digital camcorders. Also known as IEEE1394.

Firmware        Basic software permanently stored on a device (such as a graphics card) that controls it's basic operation. Firmware can be upgraded using a process known as 'flashing'.

Flash        An application used to create high-quality animations on websites.

Flash memory        A special type of memory that maintains its contents even when the host machine, like a palmtop computer, is switched off.

Flatbed        A type of image scanner that resembles a small photocopier. Place a document face down on the glass scanning bed and the scan-head is moved across it, building up a digital image as it goes.

Flat-panel display        Slim monitors, similar to the liquid-crystal displays (LCD) found in notebook computers, designed for use with desktop PCs.

Floppy disk        A small, rigid square of plastic used to store data. Inside the case is a circular magnetic disk (the floppy bit). The most common type of floppy disk is the 1. 44Mb 3. 5in version used by almost all PCs.

Folder        Files on PC's hard disk are arranged within a system of folders, which group related items together, helping you find the item you need. Folders have names to describe what's in them, for example: My Documents.

Font        A set of letters, numbers and other symbols in a particular style. Popular Windows fonts are Arial and Times New Roman

Font size        This is the measurement typographers use to describe the size of text. Thus, 72pt text is bigger than 34pt text. The text you are reading now is set in 8. 5pt.

Footer        A special area at the bottom of a word-processor document: type something in here and it will appear at the base of every page.

Form        A document formatted in a certain way for entering data, much like the paper version. Forms are typically used by databases.

Format        The process of preparing a floppy disk for use with a particular computer and operating system.

Formula bar        In spreadsheets, this is located at the top of the screen, above the grid of rows and columns. If a selected cell contains a formula, it will be visible in the formula bar. Otherwise any contents in a cell will be displayed in the formula bar. You can, for example, type text directly into a selected cell, or into the formula bar the result will be the same.

Formulas        Formulas tell spreadsheets how to act on data stored in cells. For example, '=SUM(B13+B16)' tells the program to add the contents of cells B13 and B16 together.

Fragmentation        When there's not enough contiguous room to save a file in one physical location on your hard disk, the file will be spread over several smaller locations. This fragmentation is an inevitable consequence of constantly saving and deleting files  especially if space is scarce. Eventually your hard disk will need to be tidied up, or defragmented.

Frame rate        The number of images, or frames, shown each second that make up a moving image. The higher the rate, the smoother the moving image. Games and movies in particular benefit from high frame rates.

Frame size        The size or resolution of each individual frame of video, usually set on capture and dependent on whether you require full screen or a small video window on your monitor.

Frames (web animations)        Animated GIFs contain multiple images (otherwise they wouldn't move) which are held in frames, just like those you would see in a movie reel.

Frames (web pages)        In the context of web pages, these are used to segment content. One frame might contain a menu of the website while the other displays the information that you're interested in. The frame borders might be visible but are often hidden.

Freeware        Software, often downloadable from the internet, which is then free for you to keep and use

FTP        Stands for File Transfer Protocol, which is a way of transferring files over the internet, particularly when maintaining websites.

Full duplex        The ability of a device (like a modem or sound card) to send and receive data simultaneously.

Gameport        The D-shaped socket found on most sound cards. This is used to connect game controllers and also doubles as a MIDI interface

Gamma correction        Correcting the overall brightness of an image to take into account differences between the way a PC reads an image and the human eye.

Gb (Gigabyte)        A measurement of storage capacity  usually for hard disks. 1Gb is equal to 1,024Mb (megabytes).

Gbits/s        Gigabits per second. A measure of data transfer rate equal to 1024Mbits/s or 1,048,576Kbits/s

GHz (gigahertz)        A thousand Megahertz is 1 Gigahertz. It's a measure of how fast the processor in your PC works.

Graphics card        The part of a PC that displays the image you see on your computer's monitor.

Graphics processor        A dedicated chip on a graphics card designed to controls the images displayed on a monitor.

Graphics tablet        An alternative to the mouse: you move a stylus over a small board just as you would a pen on a piece of paper.

Hackers        People who break into other people's computers and networks, often in an attempt to steal sensitive information.

Hacking        The slang term used to describe illegal access of computer systems by unauthorised users.

Handheld computer        A small computer, about the size of a spectacles case. Handhelds usually have both a screen and keyboard in a folding case. The Psion Revo is an example of a modern handheld computer.

Handles        In the context of software, small blocks that appear at the sides and corners of a selected object in certain applications. Dragging a handle with the mouse usually resizes the object.

Hard disk        A high-capacity disk drive fitted in almost all PCs and used to store both applications and the documents and files they create. Hard disks are so-called because they use rigid magnetic disks to store data. Hard disk storage capacity is measured in gigabytes.

Hardware        Your computer set-up is split into two parts  hardware and software. Software covers the programs that run on your machine, while hardware describes the physical components, like the monitor and keyboard.

HDCP        High-bandwidth Digital Content Provider. A method of protecting copyrighted digital entertainment content.

HD-DVD        A new format offering high-definition video on DVD-sized discs. Rival to Blu-Ray.

HDMI        High Definition Multimedia Interface. A specification that combines audio and video into one digital interfaces for use with DVDs,digital TVs and so on.

HDTV        High Definition Television.High-resolution, widescreen digital TV that requires both an HDTV broadcast and television

Header        A title that can be inserted at the top of the page, usually in a word-processor document.

Heatsink        a block of machined metal, usually aluminium, used to dissipate heat from a hot component, such as a processor.

High-definition        Also known as high-def or HD for short,a high-definition picture has a superior resolution to that of normal TV or video,and therefore shows more detail.

Homepage        The first or main page of a website, usually containing links to more detailed sections or content.

Host        The PC that you set up as the 'base' or central PC in your home network. It is usually attached to the printer.

Host drive        When DriveSpace creates a compressed drive, it keeps part of it uncompressed ? the host drive. It's usually a very small part of the disk, but it contains important files that allows your newly compressed drive to work properly.

HSCSD        High Speed Circuit Switched Data. An enhanced version of the GSM digital mobile phone network that can transfer data at speeds up to 28. 8Kbits/s.

HTML (HyperText Mark-up Language)        The language used to create pages for a website. HTML code is written as text that is converted to a web page by a web browser.

Hyperlink        A clickable link on a web page or in a document that takes you to elsewhere, like to another website or a later page.

Hyperthreading        Technology developed by Intel that enables one of its newest Pentium 4 processors to behave as two processors for certain tasks, speeding up performance.

Icon        A small image used by Windows to identify a file or application.

IDE        Stands for integrated device electronics, which is a standard interface for connecting devices such as hard disks and CD-ROM drives to a PC.

Image-editing application        Software used to manipulate digital images, either created from scratch or obtained via a scanner or digital camera.

Infection        Describes the way a virus transfers itself from one computer to another

Infrared        An interface that allows you to transmit data via infrared light waves,allowing data to be transferred cordlessly between devices.

Infrared port        An interface that allows you to transmit data via infrared light waves, allowing data to be transferred cordlessly between devices with infrared ports. Most PDAs and notebook computers feature infrared ports, but few desktop PCs are so lucky  limiting the usefulness as a connection method.

Ink cartridge        A plastic container holding ink, inserted into an inkjet printer. Some cartridges may incorporate the nozzles that will put the ink on the page but they are often just refills that slot into a reusable head.

Inkjet printer        Type of printer which squirts tiny dots of ink onto the page to form text and images. Almost all inkjet printers print in colour as well as black and white.

Instant messenging        Real-time text-based communication over a network (usually the internet), using a program such as AOL Instant Messenger.

Integrity check        A type of virus check comparing previously-stored information about a file to later versions, noting any suspect modifications.

Interface        In the context of software, the 'look and feel' of a program, such as its buttons, menus and windows. In hardware terms, it usually refers to a physical connection, like a parallel printer interface.

Internet        An global network that links millions of computers, using phone and cable links. Users connect to server computers, which act rather like a local phone exchange. A modem connects your PC to the server from home, allowing you to become part of the internet.

Internet Explorer        Microsoft's internet browser a program that allows you to 'browse' web pages, manage your favourite web sites, and so on.

Internet Protocol (IP) address        An identifying number of a computer attached to a network. A computer's IP address is similar to a phone number in function. Every computer must have a unique IP address  either a permanent address or one that is dynamically assigned to them each time they connect to the net. IP addresses are written as four sets of numbers separated by full stops; for example, 204. 171. 64. 2.

Internet service provider (ISP)        A company which provides you with an internet connection, either for fixed monthly fee or for the cost of local call charges. Examples of popular ISPs include BT Internet, AOL and Freeserve.

Interpolation        When scanner software increases the resolution of a scanned image by mathematically guessing extra details.

Intranet        Has the look and feel of an internet website, and can be explored with a browser such as Internet Explorer or Netscape Navigator. Unlike the web, access is limited to pages on a company's internal network.

IRC (or Internet Relay Chat)        A vast, largely un-regulated global network allowing users to type messages in real time much like a real conversation. Divided into separate rooms, or 'channels'.

IrDA Infrared Data Association        A standard that allows two devices to communicate with each other via their infrared ports. IrDA-compatible ports are often found on notebook computers.

IRQ        Stands for interrupt request, which are settings that determine the memory addresses and processor usage for PC add-in cards and devices. You shouldn't change these unless you really know what you're doing.

ISDN        Stands for Integrated Services Digital Network, which is a digital telephone connection providing high-speed data transfer, for such things as internet access. Popular in particular with businesses needing to transfer large amounts of data regularly and reliably.

Java        A special language used to create advanced effects on websites, such as animated sequences and interactive buttons and menus.

Jaz drive        A high-capacity storage device made by Iomega. Capable of storing 2Gb of data on removable cartridges.

Jitter        Read errors caused by the timing electronics inside a CD player or CD-ROM drive

Joystick        A stick-like device that lets you control actions in games.

JPEG (or JPG)        A common format for image files. JPEG images are compressed and the small file size makes them ideal for web pages.

Jumpers        Little metal pins, found on expansion cards and motherboards, which allow you to change settings manually.

Justified        Text which lines up with both page margins or both edges of a column.

Kb (kilobyte)        Measure of capacity of a storage device. Equal to 1,024 bytes.

Kb/s        Short for kilobytes per second, which is a measure of data transfer speed.

Keyword        A word of particular importance on a web page that can be used by search engines to identify it.

KHz (KiloHertz)        For digital audio, this refers to the number of samples per second a piece of music is recorded at. Audio CDs use 48KHz samples -- 48,000 samples per second.