Definition - What does Deep Web mean?
The Deep Web is also known as hidden Web, Undernet, Deepnet or Invisible Web.
Techopedia explains Deep Web
Coined by Mike Bergman, the Deep Web term relates to deep sea/ocean environments that are virtually invisible and inaccessible. Technically, the Deep Web is a series of interconnected systems that are not indexed by search engines and only directly accessible by their creators or individuals with very limited privileges.
The Deep Web contains data that is dynamically produced by an application, unlinked or standalone Web pages/websites, non-HTML content and data that is privately held and classified as confidential. Some estimate the size of the Deep Web as many times greater than the visible or Surface Web.