HTML is short for Hypertext Markup Language. You can build web pages with HTML, but essentially HTML is just a document format. Just like .doc files for Microsoft word. In fact most document editors like Microsoft Word let you save documents in HTML format if you wish. HTML documents are identified by their .htm or .html extensions.

Fun Exercise: Take a look at save as options in Microsoft Word next
time you want to save a document. Save the file as a html file. Next, browse to the file with Microsoft Explorer or your Firefox web browser you will find you will be able to open it up as a web page!! ).

HTML files are even more basic than .doc files. You can open up html files in an ordinary text editor. As an exercise open up a HTML file in notepad you will see that it just consists of text surrounded by special instructions to your web browser called tags. Tags are surrounded by angled brackets, <>.  They tell your web browser how to present the text.