H is for HTML, (HyperText Markup Language) used to create pages on the World Wide Web. In essence, HTML is a very simple programming language, so easy you can create your own Web page in an evening, yet so flexible that in capable hands it can present an interactive dissection of a human cadaver.

"Hypertext" is defined as "human-readable, information-linked together in an unconstrained way", and was coined in the Fifties. Basically, the words and symbols in the files on each World Wide Web computer tell the browser program on your computer how to display those files, including their text and pictures.

For example, when your copy of Netscape comes across , which "turns off" that typeface.

But hypertext offers a lot more than that. What a thesaurus does for word definitions, hypertext does for any sort of text and graphics. On a Web page, certain words are highlighted - click on them, and you will jump to a different file about the same subject. So if you wanted to read more about the Cern research labs - where HTML was invented earlier this decade - you would just put your mouse over those words, click, and your computer could automatically transfer its connection to Cern's Web server.

HTML inventor Tim Berners-Lee got the idea partly from old text-based computer games of Adventure, proving computer games do have some use after all.

Given that before 1990 the Web was only an idea being discussed by scientists at the European research labs of Cern, HTML has come a long way in a short time. Further extensions are constantly being planned. Like most things in computing, it's never finished - it's just being improved.