Source : Webster's Revised Unabridged Dictionary (1913)

Transmigration \Trans`mi*gra"tion\, n. [F. transmigration, L.
   transmigratio.]
   1. The act of passing from one country to another; migration.

   2. The passing of the soul at death into another mortal body;
      metempsychosis.

Source : WordNet®

transmigration
     n : the passing of a soul into another body after death