ephemeral

adj

1. Lasting for a short period of time.

   “1821-1822, Vicesimus Knox, Remarks on the tendency of certain Clauses in a Bill now pending in Parliament to degrade Grammar Schools Esteem, lasting esteem, the esteem of good men, like himself, will be his reward, when the gale of ephemeral popularity shall have gradually subsided.”

   “sentences not of ephemeral, but of eternal, efficacy”

   “It was during an access of this kind that I suddenly left my home, and bending my steps towards the near Alpine valleys, sought in the magnificence, the eternity of such scenes, to forget myself and my ephemeral, because human, sorrows.”

2. Existing for only one day, as with some flowers, insects, and diseases.
3. Usually dry, but filling with water for brief periods during and after precipitation.

   “The graben constitutes a depositional basin and a topographic low, underlain by Cretaceous shales, in which volcanic debris accumulated in ephemeral lakes and streams in Oligocene and early Miocene time.”

noun

1. Something which lasts for a short period of time.