The term 'apparition' is defined simply as a supernatural manifestation , or in more common terms, the appearance of a ghost or spirit of a human or an animal.
These strange, and often frightening, manifestations have been reported for as long as mankind has walked the earth, and are as variable and different as the people who witness them. Lets look at some of the various types of this particular phenomenon.
One type of apparition is called an 'atmospheric apparition'. These types of manifestations are not usually considered to be what experts in the paranormal would call an 'intelligent haunting', but a haunting that is more like a tape recording. Most of the time these types of apparitions stem from very violent and tragic events. The energies released from the individuals involved in these events seem to become imprinted upon the very fabric of time and space, what is known as the Akashaic record in Hindu beliefs. These events, like fierce battles that took place on a particular piece of ground, such as Gettysburg, may leave an sort of recording that replays itself over and over for a period of time. One of the interesting things about such manifestations is that they do fade over a period of time, much like a video tape will eventually wear out after much usage.
Another type of apparition are called 'historical apparitions.' These apparitions generally consist of seeing people from another time period of a certain house or area that has a particular sort of history. These apparitions are always dressed in period clothing and never seem to be aware of the witnesses or other people who may live in the residence in the present time.
One of the most common forms of this phenomenon is called 'Recurring apparitions'. These are ghosts or spirits that occur in regularly at a specific time each year. The manifestation usually occurs on the specific date or anniversary of the event which caused this sort of haunting to transpire. Such reports of recurring apparitions often include murder victims, people who have committed suicide, quite often people have reported seeing ghostly armies or soldiers marching and running across battlefields to the sounds of cannon and gun fire.
Crisis or Death Bed Apparitions are spirits of the dying or deceased individual that appear to loved ones or close friends shortly before or just after their physical death. These are probably the most common types of apparitions. These types of apparitions rarely go on for more than 3-5 days after a person's body expires. This type of apparition seems to be most common during times of war. During all the wars of the last 200 or so years, there were hundreds of reported cases of the appearances of dying or dead service men to family members even though they were thousands of miles apart. The most common ideology with this particular type of apparition is that the spirit of the departed appears one last time to take care of some unfinished business, to say a final goodbye, or let their loved ones know they are at peace.