A server is a running instance of a software application capable of accepting requests from a client and giving responses accordingly.
A server is a running instance of an application (Software) capable of accepting requests from the client and giving responses accordingly.
Servers can run on any computer including dedicated computers, which individually are also often referred to as "the server".
In many cases, a computer can provide several services and have several servers running. The advantage of running servers on a dedicated computer is security. For this reason most of the servers are daemon processes and designed by the designers in such a way that they can be run on specific computer(s).
There are various categories of servers. Please refer to this Wikipedia page to learn more about the subcategories of servers.
