medium

As I have used this word on these blogs, it is in reference to someone who acts as an intermediary between the physical world, and the nonphysical world (as opposed to, say, cooking at a medium temperature, or the avoidance of extremes)..

Psychics can pick up impressions from things or places or people in the physical world, whereas a medium in the same circumstances will relay information from a person who is present as a nonphysical entity (whether that is someone who is ‘dead’ or the astral of a person who is still alive).

Mediums may relay the information they receive, which is referred to as ‘mental’ mediumship, or allow their astral to step out and have an entity come in and control their body, for the purpose of relaying messages more directly - from the spirit’s mouth directly, even if the spirit is temporarily borrowing a physical mouth, so to speak. This is referred to as ‘trance’ mediumship - these two terms overlap considerably.

There is also what is termed "physical" or "phenomena" mediumship, where physical effects happen.

For more on this topic, see:

• http://theothersidetv.ca/ghost-hunting-resources/glossary/.

For more on physical mediumship, see:

• https://www.ghostcircle.com/physical-mediumship/, https://www.ghostcircle.com/physical-mediumship/2/, https://www.ghostcircle.com/physical-mediumship/3/ and https://www.ghostcircle.com/physical-mediumship/4/; 
• http://psychiclibrary.com/beyondBooks/physical-mediumship/;
• https://www.youtube.com/watch?v=XCGo9sHBhks; 
• https://www.youtube.com/watch?v=tW6pVFOpE6Q (original - in German - https://www.youtube.com/watch?v=o9Y5TLve7yA).

I have some pertinent comments in these posts:

• http://gnwmythr.blogspot.com.au/2010/05/briefing-for-landing-on-planet-earth.html (Stuart Holroyd's critique of mediumship is the best I've ever come across);
• http://gnwmythr.blogspot.com.au/2011/10/quality-of-medium.html; 
• http://gnwmythr.blogspot.com.au/2011/05/dawn-hill.html; 
• http://gnwmythr.blogspot.com.au/2011/04/rescuing-uncooperatives.html; 
• http://gnwmythr.blogspot.com.au/2010/11/miscellany-on-leadership-growth.html, and http://gnwmythr.blogspot.com.au/2010/07/reading-and-registers.html;
• http://gnwmythr.blogspot.com.au/2010/08/book-rave-spirit-release-by-sue-allen.html; 
• http://gnwmythr.blogspot.com.au/2010/08/rapping.html;
• http://gnwmythr.blogspot.com/2008/05/mediumship-part-three-last-part.html.

Some books which might be useful (see here for some brief reviews I did, back in the days when I didn't know how to copy text from Word documents SIGH ):

• "Out on a Limb", by Shirley Maclaine
• "Supernature", by Lyall Watson
• "The Founders of Psychical Research" by Alan Gauld
• "The Mediums” Book" by Kardec and
• "The Spirits” Book" by Allan Kardec (translated by Anna Blackwell, 1875)
• "Eileen Garrett and the World Beyond the Senses" by Angolf
• “Child Possessed” by David St. Clair