Also called an
appserver. A program that handles all
application operations between users and an organization's backend business applications or
databases. Application servers are typically used for complex transaction-based applications. To support high-end needs, an application server has to have built-in redundancy, monitors for high-availability, high-performance distributed application services and support for complex database access.
See the Server Types page in the quick reference section of Webopedia for a comparison of server types.
(Many thanks go out to Paul White, Product Marketing Manager EMEA, BEA Systems, for providing this updated definition.)