Legacy application
From AMWA
A legacy system is an existing computer system or application program which continues to be used because the user (typically an organization) does not want to replace or redesign it. Many people use this term to refer to "antiquated" systems.
Legacy systems can be exposed as services in an SOA by wrapping their functionality in appropriate service interfaces (see Wrapper). The success of this approach is very much dependent on how the legacy system was designed and implemented. A legacy system which was originally modularized along functionality lines lends itself to wrapping much more than a legacy system whose individual functional components are spread across various code modules and closely mixed with other functional components.
