First and foremost, HTML5 includes redefinitions of existing markup elements, and
new elements that allow web designers to be more expressive in the semantics of
their markup. Why litter your page with divs when you can have articles, sections,
headers, footers, and more?
The term “HTML5” has additionally been used to refer to a number of other new
technologies and APIs. Some of these include drawing with the element,
offline storage, the new and elements, drag-and-drop functionality,
Microdata, embedded fonts, and others.