What Is An Orphan Page
An orphan page is one that is not linked to by any other page on your site. This results in the search bot not being able to find it.
This can sometimes happen if you put up a page that you don’t want general visitors to be able to see, perhaps to show someone something that is not intended for general view.
Orphan pages are useless as the have no SEO benefit as they can’t be found by the search bot.