HTML is:

H.T.M.L. stands for “Hyper Text Mark-Up Language”.
What is mark-up language? The red-pen on your english essay is “mark-up”(sp?).

With html, we use tags to denote start and end points (ie: the beginning and end of sentence fragment). The start-point (opening-tag), and end-point (closing-tag) together form an html-element.

<element>This text is 'Nested' within an Element</element>

There are many different kinds of html-elements.

<!-- You can add Helpful comments to your html likeso -->
<h2>A Heading Element</h2>
<p>A Paragraph element often contains more than one sentence of 
context. A paragraph is a block-level element... I will discuss 
block-level and inline-level elements in more detail later on.
</p>
<p>
     Being the lazy-being which I am... Maybe I can get away with demonstrating:
</p>
<p>
     Block Level Elements
</p>
<p>
 vs <strong>Inline</strong> <em>Level</em> <a href="http://dabzo.com">Elements</a>
</p>
<p>In a <u>simpler</u> way</p>

Now… here is the same code when read by your internet browser.

A Heading Element

A Paragraph element often contains more than one sentence of
context. A paragraph is a block-level element… I will discuss
block-level and inline-level elements in more detail later on.

Being the lazy-being which I am… Maybe I can get away with demonstrating:

Block Level Elements

vs Inline Level Elements

In a simpler way