Palingenesis \pal-in-JEN-uh-sis\ , noun;
1. Rebirth; regeneration
2. In biology, embryonic development that reproduces the ancestral features of the species
3. Baptism in the Christian faith
4. The doctrine of transmigration of souls
According to the Oxford English Dictionary this word is probably an alteration of palingenesia, which comes from the Ancient Greek word genesis.
And no, Sarah Palin has nothing to do with it.
*Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Wednesday, December 1