A Doorway Page is a Web document designed to rank for a specific query with the purpose of redirecting or channeling a search visitor toward some other part of the Website or a different Website altogether. The idea is that a doorway page can optimize for a very specific popular keyword other than the Website’s brand names and, perhaps added by aggressively placed link anchor text, outrank other, more useful content.
A Landing Page is a Web document that is now normally used to receive visitors from advertising campaigns or non-search channels. The landing page may include embedded calls-to-action that facilitate quick, easy registration, sales, or submission of visitor data (such as email addresses and/or telephone numbers).