2 What is a server (and what is a client)?

Technically, a server is a computer, or a collection of computers, that provide a service. A client, on the other hand, is a computer that utilizes at least one service offered by a server.

Now, that is hardly useful, is it?

 2.1 An example: file serving
 2.2 Another example: web serving
 2.3 Home theatre serving