HTML5 Semantics

In HTML5 there are more semantics, personally I think this is a good thing. Instead of an endless amount of

<div>

s we have more structural elements like

<header>

,

<nav>

,

<aside>

,

<footer> 

etc I'll try and explain which I think are the main ones as best as I can, but in the mean time you may want to check out theses Cheat Sheets: HTML5 and HTML5-CSS3 the latter is a little dated but still excellent for guidance.