regeneration

Short definition from Wiktionary

Noun

1. 1
   Rebuilding or restructuring; large scale repair or renewal; revitalisation.
2. 2
   Spiritual rebirth; the change from a carnal or material life to a pious one
3. 3
   The renewal of the world at the second coming of Christ.
4. 4
   The process by which a water softener flushes out minerals extracted from the water supply.
5. 5
   The ability to rapidly heal substantial physical damage to one's body, or to spontaneously restore hit points.
6. 6
   The property of a kind of circuit, much used in radio receivers, that allows an electronic signal to be amplified many times through a feedback loop.