Tool for finding information, especially on the Internet or World Wide Web .
Search engines are essentially massive databases that cover wide swaths of the Internet. Most consist of three parts: at least one program, called a spider, crawler, or bot, which "crawls" through the Internet gathering information; a database, which stores the gathered information; and a search tool, with which users search through the database by typing in keywords describing the information desired (usually at a Web site dedicated to the search engine). Increasingly, metasearch engines, which search a subset (usually 10 or so) of the huge number of search engines and then compile and index the results, are being used.