Search Engines

A search engine represents a program that searches documents for keywords and creates a list of documents where these keywords are found.

The term refers to all kinds of programs but it is commonly used to describe systems that allow users to search for documents and files on the Internet. In the 21st century, search engines allow users to search information for all kinds of topics in millions of pages.

For more to know : https://www.questia.com/library/economics-and-business/business/industries/computers-and-the-internet/search-engines