I. ə̇ˈfem(ə)rəl, ēˈf-, (ˈ)e|f-, chiefly Brit -fēm- adjective
Etymology: Greek ephēmeros, literally, lasting a day, daily (from epi- + hēmera day) + English -al — more at hemera
1.
a. : lasting or existing briefly : temporary
ephemeral boundaries
their floors and ceilings … thin and ephemeral in appearance as a card palace — Roderick Cameron
: fleeting
jazz is perishable, ephemeral , elusive — Whitney Balliett
specifically : lasting only one day
ephemeral fever
ephemeral blossom
b. : of interest or value for only a short time : topical
were not local and ephemeral … but universal and timeless — J.P.Boyd
c. : existing in an immaterial form
ephemeral data, the businessman's unrecorded wealth of experiential knowledge of the behavior of consumers
: intangible
2. : devoted to what is of temporary interest
a medium so ephemeral as radio
prose drama is the most ephemeral of the arts … practically all plays find their resting places on the library shelves after their brief day or few decades in the theater — R.A.Cordell
Synonyms: see transient
II. noun
( -s )
: something ephemeral ; specifically : a plant that grows, flowers, and dies in a few days (as many desert and arctic annuals)