I'd imagine it's a more generic term for a small PC (or maybe an Android TV box) running something like Kodi (home media centre program), and Kodi would have access to a drive (usually a network drive) full of pirated MP4s or whatever. I'm sure there's even more elegant solutions out there, but you get the gist.
What's a media center piracy box and how to setup one?
I'd imagine it's a more generic term for a small PC (or maybe an Android TV box) running something like Kodi (home media centre program), and Kodi would have access to a drive (usually a network drive) full of pirated MP4s or whatever. I'm sure there's even more elegant solutions out there, but you get the gist.