Horcrux

The Horcrux is a "receptacle in which a Dark wizard has hidden a part of his soul for the purposes of attaining immortality."[1] With part of a wizard's soul thus stored, the wizard becomes immortal so long as the Horcrux remains intact, typically hidden away in a safe location. If the wizard's body is destroyed, part of the soul remains preserved within the Horcrux.[2] However, the destruction of the Horcrux creator's body leaves the wizard in a state of half-life, without corporeal form.[3] The dark magic involved in the creation of a Horcrux is considered most despicable and is therefore rarely published, even in books devoted to the Dark Arts.
A Horcrux can be made from any normal object, as well as living organisms. Destruction of the Horcrux destroys the fragment of soul contained within it, ending the protection it provides, and rendering the creator mortal if there are no remaining Horcruxes. A wizard must have at least one piece of his soul intact on Earth in order to continue living. Thus, if all of the Horcruxes created by one wizard were destroyed, then there would be no way for the wizard to return after being killed, as his death would release the last piece of his soul from mortal existence.[4]

The creation of a Horcrux requires the creator to commit a murder, which, as "the supreme act of evil, (...) rips the soul apart."[6] Once the murder has been committed, a spell is cast to infuse one portion of the ripped soul into an object, which becomes a Horcrux. The spell can be found in the book Secrets of the Darkest Art.
There is no apparent limitation on the nature of the items that can be made into a Horcrux; even living creatures may be used. There also seems to be no limit to how many Horcruxes a wizard can create. However, each time the soul is split and a new Horcrux is created, the creator risks losing more of his natural humanity.

Unlike normal objects, Horcruxes are notoriously difficult to destroy. They cannot be destroyed by conventional means such as smashing, breaking, or burning.

A Horcrux can be magically undone only if the creator goes through a process of deep remorse for the murder committed to create the Horcrux. The pain of this remorse is so excruciating that the process itself may kill the creator.

Poltergeist

Poltergeist(German for noisy ghost) is a term used to describe a supposed spirit or ghost that manifests itself by moving and influencing inanimate objects.

Reports of poltergeist activity typically feature raps, bumps, thumps, knocks, footsteps, and bed shaking, all without a discernible point of origin or physical reason for occurrence. Many accounts also report objects being thrown about the room, furniture being moved, and even people being levitated.

Curse

A curse is the effective action of some power, distinguished solely by the quality of adversity that it brings. A curse may also be said to result from a spell or prayer, imprecation or execration, or other imposition by magic or witchcraft, asking that a god, natural force, or spirit bring misfortune to someone.

The deliberate levying of curses is often part of the practice of magic, taking place at the boundary between organized religion and folkloric customs.

Inferius

An Inferius (plural: Inferi) is a corpse controlled through a Dark wizard's spells . An Inferius is not alive, but rather just a dead body that has been bewitched into acting like a puppet for the witch or wizard. Unlike ghosts, it is apparent that Inferi cannot think for themselves. They are created to perform a specific duty assigned by the Dark wizard who commands them, remain idle until their task can be performed. This task is then thoughtlessly carried out, whether or not it will produce any result. Inferi are difficult to harm by magic; however, they can be repelled by fire or any other forms of heat or light, When defeated, they return to their idle state.

There are two main differences between ghosts and Inferi. The first is the aforementioned fact that ghosts have an active consciousness. The second, is that ghosts are transparent and retain their sense of being. Therefore, ghosts and Inferi are opposites: one has sentience but no body; the other a body but no sentience.

Wand

A wand consists of a thin, straight, hand-held stick of wood, ivory, or metal. Generally, in modern language, wands are ceremonial and/or have associations with magic but there have been other uses, all stemming from the original meaning as a synonym of rod and virge, both of which had a similar development.

Magic wands commonly feature in works of fantasy fiction as spell-casting tools.