Wordnet 3.0
NOUN (2)
1. 
 (rare) worship that admits or tolerates all gods; 
2. 
 the doctrine or belief that God is the universe and its phenomena (taken or conceived of as a whole) or the doctrine that regards the universe as a manifestation of God; 
The Collaborative International Dictionary of English v.0.48:
Pantheism \Pan"the*ism\, n. [Pan- + theism.]
   The doctrine that the universe, taken or conceived of as a
   whole, is God; the doctrine that there is no God but the
   combined force and natural laws which are manifested in the
   existing universe; cosmotheism. The doctrine denies that God
   is a rational personality.
   [1913 Webster]
WordNet (r) 3.0 (2006):
pantheism
    n 1: (rare) worship that admits or tolerates all gods
    2: the doctrine or belief that God is the universe and its
       phenomena (taken or conceived of as a whole) or the doctrine
       that regards the universe as a manifestation of God
Moby Thesaurus II by Grady Ward, 1.0:
53 Moby Thesaurus words for "pantheism":
   Albigensianism, Arianism, Catharism, Ebionitism, Erastianism,
   Gnosticism, Jovinianism, Lollardy, Manichaeanism, Manichaeism,
   Monophysism, Monophysitism, Pelagianism, Waldensianism, Wyclifism,
   acosmism, allotheism, anthropolatry, anthropomorphism,
   anthropotheism, antinomianism, autotheism, cosmotheism, deism,
   ditheism, dualism, dyotheism, emanatism, error, fallacy,
   false doctrine, henotheism, heresy, hylotheism, hylozoism,
   mind-stuff theory, misbelief, monism, monolatry, monotheism,
   multitheism, myriotheism, philosophical unitarianism,
   physicomorphism, physitheism, polytheism, psychotheism,
   tetratheism, theism, theopantism, theriotheism, tritheism,
   zootheism
The Devil's Dictionary (1881-1906):
PANTHEISM, n.  The doctrine that everything is God, in
contradistinction to the doctrine that God is everything.