The multiplayer tag typically refers to a feature of games software where more than one user can interact with the same instance of the software.
The multiplayer tag typically refers to a feature of games software where more than one user can interact with the same instance of the software, often to participate in the same play session or to co-exist in the same persistent world.
Although multiplayer scenarios sometimes include 'hotseat' games where players take turns to play, it is more common for multiplayer to imply simultaneous play by 2 or more people, which in turn often implies the same game being played on multiple machines. As such this is typically about networking, and often has solutions that derive from those found for concurrent and distributed systems generally.