ITunes Server
"iTunes Server" is a technical specification that some network-attached storage (NAS) drive manufacturers have included on their devices if they are DAAP enabled. This means the device allows the user to store their iTunes media folder remotely onto the NAS device, whether over a wired connection (such as USB 2.0/3.0, FireWire 400/800, Thunderbolt, etc.), or wirelessly (i.e. over a Wi-Fi connection). However, the DAAP functionality can be limited, as different device manufacturers often will not support all file formats currently supported in iTunes software, when working remotely using DAAP.
Read more about this topic: Digital Audio Access Protocol