Nowadays, hardly anyone will patiently wait for Google or any other search engine to load results for more than 5-6 seconds. The technology
that ensures instant search results and a smooth user experience is called the search index. A search index
can be defined as structured data, which search engine accesses when looking for results for a specific query. The definition may sound complicated, but there is a simpler way to describe it. The search index
and book index
are somewhat alike. You might have come across indexes in large scientific books or encyclopedias. Usually, the book index
includes a list of all the important terms with page numbers, where you can find more information on the topic. This list is organized alphabetically and can be found at the end of the book.
For example, if you want to find information about dolphins in the animal encyclopedia, you would look for the keyword "dolphin" and discover that you should go to pages 23, 70-71, and 187. The search index
is somewhat similar: it allows the search engine to quickly find the information that is relevant to the user's search query.