An appliance with the primary role of storage, and the ability to share files over the network are the distinguishing features for a NAS. Network support for iSCSI, SMB, NFS makes a NAS; sharing data exclusively over the media protocols (http, rtsp, etc) makes it a media server

By "NAS" most people mean "box they bought from someone to share files on a network" - think Qnap or Synology. They'll call a "NAS" that is home-built a server, even if they do basically the same thing.

To make it more fun, you'll have people refer to "I don't have a NAS, I run FreeNAS on my server."

There is no SMB or NFS, no 'network filesystem', though I could configure one if I want. I don't believe network filesystems are faat and reliable...

... Now that I think about i did have samba set up so I could watch 3d movies on my Meta Quest 3. But who cares if that is reliable?