Simply put, an emulator mimics the outward behaviour of a system and a Simulator actually models the internal behaviour of a system.
A Flight Simulator program actually models all the principles of aerodynamics and physics while flying a plane.
An iPad emulator looks like an IPad and interacts with the user like an IPad but it is not really an IPad behind the scenes.
I do know some people who have this mixed up, I’ll give them your link 🙂