Semantics
A landmark containing content that is relevant to a specific, author-specified purpose and sufficiently important that users will likely want to be able to navigate to the section easily and to have it listed in a summary of the page.
Additional info from the ARIA specification
Such a page summary could be generated dynamically by a user agent or assistive technology.
Authors SHOULD limit use of the region role to sections containing content with a purpose that is not accurately described by one of the other landmark roles, such as main, complementary, or navigation.
Authors MUST give each element with role region a brief label that describes the purpose of the content in the region. Authors SHOULD reference a visible label with aria-labelledby if a visible label is present. Authors SHOULD include the label inside of a heading whenever possible. The heading MAY be an instance of the standard host language heading element or an instance of an element with role heading.
Assistive technologies SHOULD enable users to quickly navigate to elements with role region. User agents SHOULD treat elements with role region and an accessible name as navigational landmarks. User agents MAY enable users to quickly navigate to elements with role region.
Abstract Role
LandmarkRepresents a top-level section of a page, relevant to a specific purpose, that a user may want to scan for quickly and could appear in a site map or table of contents.
Content Categories
Flow ContentAn element that structures and organizes the body of a web document.
Allowed Descendants
Flow Children Allowed
No main element descendants allowed.
Usage
Allowed HTML elements
Implicit semantics
These elements have the role semantics by default, without needing to set the role attribute. Reach for elements with native semantics first when choosing how to implement a role in your content.
section
Explicitly allowed
article[role=region]aside[role=region]
Elements that can have any role
abbr[role=region]address[role=region]b[role=region]blockquote[role=region]canvas[role=region]cite[role=region]code[role=region]custom-element[role=region]data[role=region]del[role=region]dfn[role=region]div[role=region]em[role=region]figure[role=region]i[role=region]ins[role=region]kbd[role=region]mark[role=region]output[role=region]p[role=region]pre[role=region]q[role=region]samp[role=region]small[role=region]span[role=region]table[role=region]tbody[role=region]tfoot[role=region]thead[role=region]time[role=region]u[role=region]var[role=region]