Web Service a (!&$#) definition please!!

What is a Web Service?. Is it a program/process that is accessed over the internet
via http using :
-SOAP
-WSDL
-UUDI
-XML

This is what my intuition is telling me. This is my definition, although I could
be wrong. Being familiar with RPC on Unix systems,
a Service is accessed by a server.



What I am very frustrated about is that I have a book on Web Services and they seem
to be dancing around a concrete definition of what a web service is. They are throwing
out information on SOAP, WSDL, UUDI and XML and seem to imply that all of these combined
make up a web service. Is this true? Please save me from this rhetoric. Their definition
of a Web service is as follows, but I like mine better.


Web Services are extensible Markup language (XML) Applications
mapped to programs, objects or databases or to comprehensive
business functions.

There's pretty much a happy medium between the two definitions. I agree that buzz words like this are thrown around WAY too much anymore. As I see it (i'm no expert, but i use these so called "web services" all the time) a server is the middle man in passing data from a point or pool of sources (in the becoming a business standard XML format) to a program residing on the server, or a connected computer. But, for the most part, the term "web services" is generally useless, it's completely vague. The marketing guru's over at MS in their infinite wisdom (do you feel the sarcasm?) decided to pitch their XML and upcoming .NET stuff in a new category they dubbed 'Web Services'. So don't get hung up on the name, it's pretty much crap if you ask me.