Key HTML5 structural elements

aside

The <aside> tag defines some content aside from the content it is placed in.
The aside content should be related to the surrounding content.

figure

The <figure> tag specifies self-contained flow content (like images, diagrams, photos, code, etc).
The content of the figure element should be relevant to the main content, but if removed it should not affect the flow of the document.

footer

The <footer> tag defines the footer of a section or document. Typically contains the name of the author, the date the document was written and/or contact information.

header

The <header> tag specifies an introduction, or a group of navigation elements for the document.

menu

The <menu> tag defines a list or menu of commands.
The <menu> tag is used for context menus, toolbars and for listing form controls and commands.

nav

The <nav> tag defines a section of navigation.

section

The <section> tag defines sections in a document. Such as chapters, headers, footers, or any other sections of the document.