It has one definition to marketing people, another for programmers, and yet another for networking people. For network people, client/server just means that a client makes a request to a server for resources. In the case of the web based client/server application, a relatively dumb client (your web browser) requests services from a Web based server application that is typically accessed via the HTTP protocol. The server does the processing and returns the data to the browser via HTTP.
This was first published in May 2002