A:

Angel - a spirit or guide. Also known in terms of fallen angels, or angels of heaven.

Apparition - a visible manifestation of a spirit, sometimes full-bodied. 

B:

Bhoot - (Hindu Ghost) usually in white clothing or cloth. Notably has no shadow. 

Bigfoot - an ape-like creature. Has many different names throughout different cultures.

C:

Camcorder - a device used to record/film/photograph locations.

Conduit - an item that is used in communication with spirits.

Cryptid - a creature whose existence or survival is disputed or unproven, such as the Yeti or Bigfoot.

Cryptozoology - the study of cryptids, including history and potential evidence to their existence.

D:

Demon - The most dangerous form of paranormal entity - these are classed as evil spirits, known for actions like possession and physical harm.

E:

EMF - this stands for Electromagnetic Field. Paranormal entities are often thought to emit or use EMF energy.

EMF Reader - a device used by paranormal investigators to detect and record unusual EMF readings and spikes.

EVP- this stands for Electronic Voice Phenomena. It is used to describe the anomalous speech-like sounds often found on electronic recordings.

F:

Fairy - a small, historically mythical being similar to that of a small human with supposedly magical powers.

Funnel Ghost – this type of behaviour is often exhibited by spirits that reside in homes or old historical buildings. This attribute is given to spirits which intend or pose no threat to the living, and may instead be helpful or at least neutral. It is believed that Funnel Ghosts may be loved ones returning to the living world. The term comes from sightings of ghosts that have a swirling funnel light shape to them on camera.

G:

Ghost- an apparition of a dead person which is believed to appear or become manifest to the living, typically as a nebulous image. 

H:

Haunting - the action of haunting a place. 

I:

Infestation - to be over-run or infested by spirits. This may range from harmless presences to full-on demonic invasions.

Infrared - a wavelength used by certain devices. Used in low light to see in grey, black, and white format imaging. 

Intelligent Haunting – this behaviour attribute is given to spirits is aware of your presence. They may attempt to communicate with the use of technology, or even basic sounds or movement. While this attribute is not inherently dangerous, the more dangerous forms of spirit almost always involve the Intelligent Haunting attribute.

Imp - class spirits are described as troublesome and mischievous more than seriously threatening or dangerous, and as lesser beings rather than more important supernatural beings. An imp may share similar features with other spirits, such as the Poltergeist, when causing mischief. Imps may be more active throughout investigations than other spirit classifications. Imps may be considered a lesser form of the Demon classification, and so should still be treated with care.

J:

Jinn - a type of spirit originating from Arabic and Islamic mythology. Often associated with demons, however can sometimes be supportive.

K:

K2-Meter - a particular model of the EMF Reader popular with investigators for its reliability. 

L:

Laser Grid - a pen-like object that emits a laser onto a wall or object. Can be used to detect movement.

M:

Microphone - used to record noise via a camera, camcorder, mobile phone or voice recorders.

Mare - a spirit classification that can be potentially animalistic. Unique quality of pressuring a chest or other body parts during sleep. “Riding” a chest is thought to induce nightmares. Sleep paralysis may be possibly caused by a Mare’s influence.

N:

Night Vision - to see in the dark or low light.

O: 

Orbs - a sphere shaped light like movement that changes direction. (careful, dust is often mistaken as orbs! Check your surroundings.)

Obsession - to be obsessed by someone, something, or some action.

Ouija Board - they are also called "spirit boards" or "talking boards. It is a flat board with the numbers 0-9 and all the letters of the alphabet. They are typically used to summon or communicate with spiritual entities.

Ovilus - an Ovilus is a piece of equipment used by ghost hunters and paranormal investigators to communicate directly with spirits  

P:

Pareidolia - is a tendency for perception to impose a meaningful interpretation on a nebulous stimulus, usually visual, so that one sees an object, pattern or face where there is none.

Phantom - This classification is given to spirits that appear extremely briefly - for example, as flashing images, shapes or faces, but more often as brief appearances of light. Phantoms are often associated with causing Pareidolia.

Poltergeist - a classification of spirits given to entities which show a behavioural trait of frequently making noise with, moving, and throwing objects.

Possession - to own or have a right of belonging to you / to be possessed by a spiritual entity such as a demon.

Psychic - a medium that can communicate with the deceased.

Portal - an intangible gateway thought to allow spirits to cross into and out of the world of the living.

Q:

Quartz - a crystal stone used in wiccan practice.

R:

REM Pod - the REM Pod is a piece of equipment which radiates EMF energy. It also has alarm settings linked to an antenna, in which it will sound an alarm if anything gets near or touches the antenna piece. Useful for detecting the movement of paranormal entities.

Residual Hauntings (Stone Tape Theory) – This attribute is the weakest form of activity. The spirit is unaware of living presence, and may be unaware that they themselves have passed away. It is, effectively, a haunting on loop, and certain actions such as a key memory or the moment they died may be repeated each sighting.

Revenant – generic term given to “undead”, such as a raised corpses, skeletal appearance, and general undead appearance. Originates from Old Irish and Norse folklore. In modern day, it is rare to see an apparition that will classify as a revenant. The unique identifier is an undead appearance.

S:

Sceptical - someone who has doubt or reservations of a situation.

Shade - also known as a shadow person, it is a type of spirit defined by the behavioural trait of manifesting as a dark shadow. This could be in the form of peripheral vision, or full manifestations.

SLS Camera - a Structured Light Sensor camera is a skeletal mapping device that detects humanoid figures and maps them on a monitor. This becomes very useful for physically detecting the potential presence of a spirit.

Spirit - the remaining energy and soul of someone or something that has passed. They are no longer part of the living.

T:

Thermal - relating to heat.

U:

UFO - Unidentified Flying Object.

V:

Vision - to see, either in spirit world or in our world a spirit.

W:

Wendigo - Mythical creature from Native East Candian/North American folklore. The Wendigo spirit is said to possess humans and induce urges for murder and cannibalism. Extremely rare and can only be found in North American regions. Not present in the UK.

Witch -a human thought to have magic powers. Witches may practice various kinds of spells from various different followings (Such as Wiccan/Pagan Witchcraft). Witches are not inherently evil, however many use their supposed abilities for nefarious reasons.

X:

Xenoglossy - is the ability to speak or write in a language that has not been learned and appears to be fabricated and non meaningful.

Y:

Yeti - a large ape-like creature thought to inhabit the upper reaches of the Himalayas. Sightings and stories of the Yeti are common in India, Nepal and Bhutan. This is one variant of the generalised creature "Bigfoot".

Yurei - the equivalent to Japan as what the western world know as "ghosts." 

Yokai - another form of Japanese spirit - Yokai are commonly associated with demonic or evil intentions, however they are also sometimes seen as simply mischievous and even sometimes helpful.

Z:

Zooform Phenomena - the term describes entities that outwardly resemble animals, but appear supernatural rather than corporeal.