Medium's meeting (6)
I believe the answer is:
seance
'medium's meeting' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for seance that I've seen before include "Medium's meeting" , "Spiritualist meeting presided over by medium" , "Meeting for communicating with spirits" , "Spiritualist meeting to contact the dead" , "Encase (anag)" .)