Apparitions -- This can include anything, from a ghost, which is typically believed to be the spirit of a deceased persone, to a vague, shadowy shape that cannot be fully described.

Ghosts -- As stated above, usually used in reference to the spirit of the deceased.

Poltergeists -- Mischievous spirits, that cause bizarre things to happen, such as plates flying across the room and objects being moved around.

Spirits -- The incorporeal substance of humans that remain after death, the soul, the mind/energy that exists in a different level of existence from our physical world.

Entity -- Generalized description used for unknown phenomenon that could be anything from a ghost to a demon to an angel, but more often used to refer to a negative energy that seems to display intelligence.

Demons -- Negative entity thought to be an angel cast from heaven to hell, having an entire hierarchy of demons complete with names...some people believe humans can be possessed or oppressed by demons, others believe what we call demons are more likely negative thought forms or negative energy that originates with humans themselves. There is an entire field of paranormal studies called Demonology that is devoted to the study of demons.

Angels -- Divine creatures that are positive, and have an entire hierarchy complete with individual names, created by God as messengers and protectors and even divine warriors, including Guardian Angels, Archangels, Cherubim, and more...familiar names of angels are Gabriel and Michael, for example.

Astral Body -- Essence of the mind that is believed to be able to separate from the living body at will and travel to other locations...some case histories exist of sightings of these astral bodies.

Shadow People -- Dark, shadow like creatures of supernatural origin that appear as dark forms in the peripheries of people's vision and disintegrate, or that move between walls, when they are noticed...they typically are described as not having any human features, and that sometimes appear to be threatening.

Spirit Guides -- Positive entities whose purpose is to assist human beings spiritually...some claim to have seen their spirit guides, which appear to them in a ghostly form, others 'sense' their presence...some believe it's just another term for angels.

more to come....