Domain Controller vs Server

In Windows 2008 it is called Active Directory Domain Services. See this for example:

http://technet.microsoft.com/en-us/library/cc755258%28v=ws.10%29.aspx

A server is simply a collection of hardware (a box) that runs a server operating system. Usually the hardware is far more redundant and efficient than what you would find on a typical PC. With that said, you could always install server software on a PC if you were so inclined (though I wouldn't recommend it). Sometimes the hardware has been tested and approved by big name server software developers such as Microsoft; which has servers that are certified to run MS Server 2003 Data Center Edition. A domain controller is a server, and one of it's functions is to act as a domain controller. The term domain controller is used to describe a "role" the server plays, not to differentiate it from one server or another. Much like you can have a server perform the role of being a print server, file server, exchange server, etc....sometimes a single box will perform many roles.

Fetched from :-
http://forums.devshed.com/networking-help-109/can-someone-explain-domain-controller-vs-server-580836.html

A Domain controller is a Server.

A server provides services and Active Directory is a service.
Other services like:
- webserver
- DNS/DHCP
- NFS/CIFS
- FTP
- SSH
- NTP
- SMTP/POP3/IMAP
- ...
                           
You can run different Operating Systems to provide those services. But you still have a server.

http://en.wikipedia.org/wiki/Server_(computing)

So, a DC is a computer (server) with a version of Windows Server (03, 08, etc) installed on it that also has Active Directory installed on it.

Is that a correct statement? Anything to add to that?

Yes, that is correct.