A gateway page is the initial page that your visitors will see. These are the pages which have a flash intro, or an "Enter Here" graphic. Gateway pages offer the opportunity to create a page which is optimum for search engines to index your page. But this must be done carefully for the full effect.
Also known as a "jump," "doorway," or "bridge" page. In order to optimize a Web site's ranking with search engines, some Webmasters build gateway pages, pages customized to each search engine with specific meta tags and keywords. These pages are intended to appeal to search engine robots, and aren't always visible to customers who visit the Web site.
Some are the same as divider pages, such as the For Students or For Faculty gateway; others lead to whole subsites (e.g., For Alumni or For Parents)