meta search engine
There are various search engines such as Google, Altavista, Lycos, Bing or Yahoo, each of which evaluates its own databases forsearch queries. Since the search engine operators used different search algorithms, the search results are inevitably also different.
In the case of an exact search with complete results, the search queries would have to be carried out in several search engines. It should be noted that search results from different search engines can be identical and therefore appear several times.
Meta search engines take over the function of the superordinate search in several search engines. They thus represent a superordinate (meta in Greek means: above) search engine that directs the search query to several search engines and matches and processes their results for duplicates.
Metasearch engines use their own algorithms and ranking for the processing. The presentation of the results pages( SERP) corresponds as far as possible to that of known search engines, naming the search engine from which the search result originates.
A well-known international metasearch engine is MetaCrwler, in Germany there are Apollo7 and MetaGer from the RRZ of the University of Hannover.