1. 1. The belief that the dead communicate with the living, as through a medium.
   2. The practices or doctrines of those holding such a belief.
2. A philosophy, doctrine, or religion emphasizing the spiritual aspect of being.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.