In the scientific community, the word "Ghost" has numerous definitions. However, an "Entity" is the conscious energy form that once inhabited a human body. An Entity exists in real time and retains the same personality possessed when previously alive. "Ghost" is the most common term used by the lay person worldwide to describe what scientists call an Entity.
People tend to place ghosts and spirits into one broad category. While this may seem acceptable at first glance, there is a whole world of difference between the three. Poltergeists and spirits are very rarely connected with ghosts.
A ghost can best be described as a form of recording, similar to an audio or video tape. There is no life force left; a ghost simply ‘plays’ the same scene over and over. A ghost is simply the residual energy of a person, animal, or even an inanimate object. Usually, if a person has performed a repetitious act for a long period of time, he or she will have left a psychic impression or ‘groove’ in that area. This ‘groove’ may stay in the area long after the person who created it has moved on or died.
This psychic ‘groove’ is very vivid when it is first encountered. The apparition, or recording, appears as if it were real. Clothing and facial features are clearly seen. Perfume or other scents are even noticed. Over time, the ‘groove’, or ghost, will get weaker, but can be recharged under the right circumstances.
A spirit, on the other hand, is the actual living essence, or soul, of a person that has remained after their physical body has died. Spirits usually appear for one of three reasons. First, if a person died suddenly or with little warning, as in the case of a car accident, he or she may not actually realize that they are dead. Second, a person could be confined to this world by an unkept promise made to a loved one. Third, he or she may have some unfinished business, usually pertaining to a loved one. A variation of this reason would be if the person was murdered at an untimely point in their lives.
Spirits, unlike ghosts, can communicate with the living. Usually, if a person frequents a place where the deceased spent much of his or her time, a form of psychic communication can result. Sudden and unexplained feelings of sadness or melancholy are common indications, especially if encountered only in one particular room or area. Another way that a spirit can communicate with the living is through dreams. Although much rarer, a spirit can make itself appear as an apparition or make small items physically move.
In the context of Parapsychology, a building, house, or area is considered 'haunted' when paranormal activity can be documented repeatedly over a period of time. Paranormal activity however, can vary dramatically from case to case and some paranormal activity is not associated with the presence of an Entity.
If you have events taking place in your home repeatedly, with no logical explanation, than there is the possibility that your home is haunted. Paranormal activity can vary greatly but some of the most common indications of a haunting include apparitions, cold spots, mobile and temporary electro-magnetic fields, poltergeist activity, objects disappearing and reappearing at a later time, and sudden behavioral changes of the home's occupants.