A web page submitted to a search engine (spyder) to give the relevance-algorithm of that particular spyder the data it needs, in the format that it needs it, in order to place a site at the proper level of relevance for the topic(s) in question. (This determination of topical relevance is called "placement".)

A gateway page may present information to the spyder, but obscure it from a casual human viewer. The gateway page exists so as to allow a web-site to present one face to the spyder, and another to human viewers. There are several reasons why one might want to do this. One, is that the author may not want to publicly disclose placement tactics. Another is that the format that may be easiest for a given spyder to understand, may not be the format that the author wishes to present to his viewers for aesthetics. Still another may be that the format that is best for one spyder may differ from that which is best for another. By using gateway pages, you can present your site to each spyder in the way which is known or thought to be best for that particular spyder.
Also known as bridge pages, doorway page, entry pages, portals or portal pages.

Similar terms: 'gateway page', 'entry page', 'bridge page' and 'portal page'