A search engine that does not compile its own independent results, but rather pulls data from two or more search engines, such as Dogpile.com.

  Search engines that automatically submit your keyword search to several other search tools, and retrieve results from all their databases.

a program that automatically searches multiple search engines at a time. Examples include www.dogpile.com and www.metacrawler.com. These can be very successful, but sometimes the results are less clea [..]

a type of search engine that scans multiple search engines simultaneously and provides results based on the keyword(s) submitted

Rather than querying each search engine individually, a meta-search engine submits your query to multiple search engines, returning results from all the engines simultaneously.

Is a search engine where different OTA websites are consolidated, so that rates and listings can be compared. Often referred to as 'Comparison', 'Consolidator' and/or 'Aggregator' sites.