The Free On-line Dictionary of Computing (30 December 2018):

service-oriented architecture

    (SOA) Systems built from
   loosely-coupled software modules deployed as services,
   typically communicating via a network.  This allows
   different modules to be implemented and deployed in different
   ways, e.g. owned by different organisations, developed by
   different teams, written in different programming languages,
   running on different hardware and operating systems.  The
   key to making it work is interoperability and standards so
   that modules can exchange data.

   SOAs often support service discovery, allowing a service to
   be changed without having to explicitly reconnect all its
   clients.

   Many different frameworks have been developed for SOA,
   including SOAP, REST, RPC, DCOM, CORBA, web
   services and WCF.

   (2009-01-23)