More than one search engine may be searched at a time using meta search engines. Regular search engines collect URLs in their own databases and search these databases when you ask them to look for something. A meta search engine does not create its own database. Instead, when you tell it to search, it searches the databases of several other search engines.
Here are several meta search engines listed with the databases they search:
Although meta search engines search through larger amounts of information than other search engines, they do not return a massive number of results. Instead, they rank their results and show you only the best matches for your search. And as with regular search engines, always check the help screen to see what search features are available. The more precise the search the more precise the results.