To begin an understanding of HTML you need to understand a few key terms which will be used frequently in this document. First, HTML is a tagged page definition language which means that HTML defines how a page will look by using tags to define features and elements of a page.
Information describing the document, creator and purpose go here, the title for example.
The iewable portion of the document and its code go here. Most, but not all, HTML tags follow this format and these are considered containers. Everything contains within these tags is influenced in some way by the tag. Thus we have a document enclosed in the open and close HTML tags which is therefore defined as being an HTML document. The document illustrated above has open and close HEAD tags and open and close BODY tags as all properly constructed HTML documents should have.