Gerund functioning as an uncountable noun meaning 'the act or process of dissipating'.
Translations
The dissipating of the morning mist left the valley bathed in sunlight.
La dissipation de la brume matinale a laissé la vallée baignée de soleil.
Definitions
The act or process of dispersing or wasting something. The dissipating of the morning mist left the valley bathed in sunlight.