Embedded Server:
An embedded server is typically a part of a bigger solution and provides dedicated services to that solution. Some embedded servers are pre-installed in devices and run out of main memory (ie. diskless).

An embedded system is a special-purpose computer system, which is completely encapsulated by the device it controls.An embedded system has specific requirements and performs pre-defined tasks, unlike a general-purpose personal computer.
From : en.wikipedia.org/wiki/Embedded_systems