What are Web Services? (1)
The term Web Services refers to an architecture that allows applications to talk to each other.
-Adam Bosworth
Basically, Web Services are a means of allowing applications to talk to one another using XML messages sent via the standard Web protocol HTTP (...)
[1] A Web service is a software system identified by a URI [RFC 2396], whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by Internet protocols.[2] A collection of EndPoints.