HTML is short for "HyperText Markup Language". This simply means it is a language for describing web-pages using ordinary text. Every web page is actually an HTML file. Each HTML file is just a plain-text file, but with a .html file extension instead of .txt, and is made up of many HTML tags as well as the content for a web page.
It is relatively easy to learn, with the basics being accessible to most people in one sitting; and quite powerful in what it allows you to create. It is constantly undergoing revision and evolution to meet the demands and requirements of the growing Internet audience under the direction of the W3C, the organisation charged with designing and maintaining the language.
HTML consists of a series of short codes typed into a text file by the site author — these are the tags. The text is then saved as a HTML file, and viewed through a browser, like Internet Explorer or Google Chrome. This browser reads the file and translates the text into a visible form, hopefully rendering the page as the author had intended. Writing your own HTML entails using tags correctly to create your vision. You can use anything from a rudimentary text editor to a powerful graphical editor to create HTML pages.