Is there a difference between a ghost and a demon?

no, a demon is just a more powerful entity but it is still a ghost, a ghost is just an afterlife life term that we call people or creatures who have passed away and have not crossed over. Now there is a difference between a spirit and demon, spirit they can still hurt you but they are more confused and stressed then a demon, a demon hurts you out of anger, a spirit hurts you because they want you to feel their pain or they are trying to get your attention.