A Ghost:

Is the disembodied soul of a deceased person that has not successfully crossed over to the other side. Ghosts become attached to a location for many different reasons that we will never be able to explain. They also do not feel as if they are deceased and do not know to cross over.

A Spirit:

Is a person who has passed away and has successfully made the transition over to the other side. They often get mistaken for being a ghost, but unlike a ghost they are not stuck here in this world and often just come to visit with us and return back over as often as they would like.