Orphan Page

A page with no links to it. This is problematic from an SEO perspective because web crawlers discover pages and index them by following (essentially clicking on) links on the pages it knows, so there is no way for search engines to know about an orphan page unless it’s included in the site’s XML sitemap submitted to the search engine. Even if it does appear on the sitemap, it’s unlikely that the page would appear in the webmaster’s desired SERPs because there would be no authority being passed to that page from other pages. It also limits the structural context that the search engine has on that page.