Fount

From the White Wolf Wiki, the most complete White Wolf reference

fount: a plumbing fixture that provides a flow of water

Fount was the term used by magi in the Dark Ages to describe their inner potential for manipulating magic.

Later, in the Dark Fantastic, this inner potential would be recognized as a seperate entity, the Daemon. In the modern nights, it will be known as the Avatar.

The mages of the Dark Ages were largely unaware that their Fount was actually a seperate entity which enabled the use of magic. The matching between these Avatars and their host mages was so perfect (enabled by the continued existence of Psychopomps) that the Avatar's own voice was quieted. While in theory this perfect joining was a good idea, in practice the Avatar's constant challenging of the mage acted as a sort of conscience and guide. Without this inner voice, many mages fell prey to infighting and hubris.