What are Linked Domains?
Linked domains are those domains to which a specific website links.
If your website links to another website, this website will be a linked domain for you. It is the opposite of referring domains which are those that link to your site.
For example, if you have an article that contains a link to Wikipedia.org, then Wikipedia.org becomes a linked domain for your website.
So linked domains are all the external sites and web pages that your website links to as references or resources. They are the outbound links rather than inbound links pointing back to your own site.