Definition of poltergeistism:
(n) :
(parapsychology) An unseen ghost which makes noises and causes disruption, especially by causing physical objects to move or fly about.
(n) :
(planets) A planet in Lich star system, Milky Way Galaxy, Virgo constellation; One of the pair of planets that were the first exoplanets which were discovered. A planet in orbit of the pulsar Lich (PSR B1257+12)