A sitewide link is an outgoing link (internal or external) that appears on every page of a website.
The most common examples of sitewide links are links the footer and the site navigation menu.
Here’s an example of sitewide links on our blog:
In linkbuilding, sitewide links are backlinks from a website that appear on its every page. In most cases, such links are unnatural and thus violate the Google Spam Policies.