A search engine is a program that retrieves information by searching a database for items that match a user's input request.

A computer program allows users to enter a query to retrieve information (e.g., files, websites, web pages) from that program's index (i.e., a web search engine, such as Google, indexes websites, web pages, and files found on the World Wide Web ).

A search index is built and updated using a crawler, with items being analyzed and ranked by a series of algorithms.

Also known as search , search , or simply searchers, examples of search Google , Bing, DuckDuckGo, and Yahoo.