Google indexing is the process by which Google crawls the web, reads the content on web pages, and adds it to its database of pages that it has seen. Google's index contains a vast collection of web pages and is continually updated with new pages and changes to existing ones. When a user conducts a search on Google, the search engine looks through its index to find pages that match the user's query, and then it ranks those pages based on how relevant and useful they are. Google uses a complex algorithm to determine the ranking of web pages, taking into account factors such as the relevance of the page's content to the user's query, the page's content quality, the number and quality of links to the page, and many other factors.

    When a page is indexed by Google, it means that Google has visited the page and has added it to its database. If a page is not indexed, it means that Google has not yet visited the page or that it has determined that the page is not suitable for inclusion in its index.