Someone who doesn’t eat enough and makes me look fat. Okay, jokes aside…
A medium is someone who can channel spiritual entities or spiritual energy. They are the medium through which the message is conveyed. They often learn through participation in circles and séances and most frequently they attempt to convey messages from the dead. They frequently speak of spirit as if it is one entity and they are frequently members of spiritualist churches. Many of them use spirit guides to help them communicate with spiritual reality.
See also other types of Magical Practitioner.