A Server is a computer, a device or a program that is dedicated to managing network resources. They are called that because they “serve” another computer, device, or program called “client” to which they provide functionality.
There are a number of categories of servers, including print servers, file servers, network servers and database servers. In theory, whenever computers share resources with client machines they are considered servers. However, servers are often referred to as dedicated because they carry out hardly any other tasks apart from their server tasks.
Source: Server