Dark web

The term dark web is used to refer to any internet site that has requested it not be searched by search engines, like Google's browser, or the Bing browser.

Although the term has negative connotations, because some dark web sites, like Pirate Bay, were places where individuals met, anonymously, in order to try to conduct clandestine transactions, there are reasons an organization might choose to not have their pages searched by search engines that have nothing to do with crimes.