The term Index, which not only applies to Google but any search engine, such as Yahoo and Bing, is the search engine listings. To be “indexed” means that your site appears somewhere in the index of search engines.
The sites home page maybe indexed, and usually other content pages of the website, referred to as “inner pages” or “sub pages” will get indexed as well.
Contrary to popular belief, not all sites will get indexed, and certainly not all pages of the site will get indexed... Read the full article