A server stack is the collection of software that forms the operational infrastructure on a given machine. In a computing context, a stack is an ordered pile. A server stack is one type of solution stack -- an ordered selection of software that makes it possible to complete a particular task.
A client stack includes the operating system (OS) and its supporting software as well as runtime environments, such as the Java Runtime Environment (JRE). A server stack includes, in addition to those elements, database software and the requisite support software for a variety of programming languages. The server stack may also include server software for various Web services.