Base Font - This is the basic font of the page, and depends on the web browser's user's preferences. It is risky to assume that the font will be any particular size.
CGI (Common Gateway Interface) - Environment in which programs or scripts run on a Server to perform operations, including generating web-pages on-the-fly when asked to by a client browser. An example of this might be a search engine that takes your search string, and runs a cgi program which generates a page consisting of the results of the search.
CPU - Central Processing Unit. This is the chip inside your computer that makes most of the calculations that are required to operate software.
Client/Server - A way of doing things, such that one machine (the Client) asks the other (the Server to do something such as provide it with information. On the Web, the client is the computer in front of the person doing the browsing, whilst the server is generally a bigger and more powerful machine on which this information is stored.
Client-Side - When one computer contacts another, the one who makes the call becomes known as the "Client" machine. So when you dial in to a website, that website is stored on a large computer called a "server", and your computer becomes the "Client". If the page contains some operation (in this case an imagemap), that is downloaded onto your machine before it is executed, then that operation is running "Client-Side", as opposed to "Server-Side".
Downloading - Copying information from a server to a client. This is what your browser does when it reads a website. It transfers the information from the place where the website is stored, to your machine. The opposite of this is called Uploading.
Hexadecimal - This is a system of counting that uses a base of 16, instead of 10, like decimals. So, as decimals go 0123456789, hexidecimals go 0123456789abcdef. Counting works exactly the same, but using more digits. So the last 2 digit number in decimals is 99, while the last 2 digit number in hexidecimals is ff.
High-Level Programming-Language - A programming language which attempts to be closer to some human language (generally English), and is thus easier to understand. BASIC is a good example of a high-level programming language. The resemblance between what the programmer writes, and what the computer actually does is not close, and another piece of software is required to make the machine understand the program.
Internet - Collective name for all the millions of computers and the connections between them which constitute the largest network on the planet. Your computer is connected to the internet if it can talk to any other computer on the internet using one of the standard protocols.
Interpreted Language - A programming language which requires another program (an interpreter) to run at the same time on the same machine, to perform its functions.
Mutually Exclusive - If several events are mutually exclusive, then at most one can be "on" at any one time. If there are 20 buttons, and they are mutually exclusive, with regard to being "on", then if one of them is "on", then the others must be "off".
Nesting - This is where one command is put inside another. For example, if we were making some text that was bold and italic, then we should put <b><i>Text</i></b>. See that both the italic tags are between the two bold tags. This could just as legitimately be written: <i><b>Text</b></i>. As you can see, as long as the nesting is correct, then the order of the tags is not so important.
Pixel - Abbreviation of "Picture Element", a pixel is the single smallest unit on the screen of a computer, ie, a single dot.
Protocol - A defined way of communicating, in this case between two computers. Essentially, it is a list of the possible things each can say, and what this means, and this allows information to be passed.
Source - This is the raw text of the HTML document. What you see in the browser window is an interpretation of that source. If you want to see the source of a page, most web browsers will have a "View Source" option somewhere - often in the "View", the "Document", or the "Page" menu, if there is one.
Syntax - This just means the way that something is layed out. If it has a specific way that it has to be written, then that is the syntax.
Thumbnail - This is a smaller version of an image that you have on your website. It is used mainly for having large indexes of pictures to look at, with the thumbnail giving you an idea what they're like. The way I've described making thumbnails is one way of doing it, but it requires quite a lot of CPU time, thus not making the page load any faster, which is often the point of thumbnails. The best way to do it, if you can, is to actually shrink the image yourself using some graphics software, and then the save it as something else, and use that instead.
URL - Universal Resource Locator. This is what you type in to find the website that you want to look at.
Web Browser - Software on the user's machine that can download and interpret information from the Web, and present it on the screen. More common examples would be Netscape, or MS Internet-Explorer.
Web, the - This is a term meaning the information that is stored on, and accessable via the internet, using a web browser. This doesn't include Usenet, or Email.