What is Search Engine?
A (usually web-based) system for searching the information available on the Web. The search engine has an interface that allows you to type what you're looking for into a blank field. It then gives you a list of the results of the search. When you use a search engine on the Web, the results are presented to you in hypertext, which means you can click on any item in the list to get the actual file.
Some search engines work by automatically searching the contents of other systems and creating a database of the results. Other search engines contains only material manually approved for inclusion in a database, and some combine the two approaches.