Google is an example of a search engine.
 

When you enter your search in a search engine, it searches within its own database of web pages for the keywords you enter, wherever they appear on a Web page.  Note that Google automatically inserts AND between terms.     Permission to reproduce Google™ image pending.

Use search engines:

- to find specific terms or phrases 
- to find well-known entities, such as IBM or government agencies
- to find news, travel and shopping services
Other search engines include:  Dogpile.com, MSN Search, Ask.com,  Alta Vista.