what is h1 or h2.... in HTML.

Headings and subheadings. The bigger the number, the smaller the heading. The heading tags go like this from largest to smallest: <h1>These</h1> <h2>headings</h2> <h3>get</h3> <h4>smaller</h4> <h5>and</h5> <h6>smaller!</h6>

these are the headings and subheadings. h1 text is bigger than h2 h2 is bigger than h3 .....so on.... h5 is bigger than h6.