evanescence
1. [ noun ] the event of fading and gradually vanishing from sight
Examples:

"the evanescence of the morning mist"

Related terms: disappearance evanesce
2. [ noun ] the property of lasting for a very short time
Synonyms: ephemeralness fleetingness ephemerality
Related terms: transience
Similar spelling:   evanesce
  evanescent
  evenness