Meta Search Engine
A search engine that gets listings from two or more other search engines, rather than through its own efforts.
Information placed in a web page not intended for users to see but instead which typically passes information to search engine crawlers, browser software and some other applications.
Allows page authors to say how they would like their pages described when listed by search engines. Not all search engines use the Meta description tag.
Meta Keywords Tag
Allows page authors to add text to a page to help with the search engine ranking process. Not all search engines use the Meta Keyword tag.
Meta Robots Tag
Allows page authors to keep their web pages from being indexed by search engines, especially helpful for those who cannot create robots.txt files. The Robots Exclusion page provides official details.