Mediums act as a intermediary between this world and the spirit world. By psychic communication the medium can channel information and messages of relevance to you.
The self-mastery to use one's psychic ability to register the presence of a Spirit communicator or Spirit companion and to work in cooperation with that reality.
the faculty(ability) of mediums. Also called channelling in some places. There is a large number of types of mediumships which the interested reader can find it in "The mediums´ book" by Allan Kardec.