evanescence

noun

1. the event of fading and gradually vanishing from sight

   noun.event

   Examples

   The evanescence of the morning mist.

   Source: WordNet 3.0

2. The act or state of vanishing away; disappearance; as, the <i>evanescence</i> of vapor, of a dream, of earthly plants or hopes.

   noun

   Source: webster1913