ephemerality Definition

1. Lasting a short time.

Thesaurus: passing, momentary, transient, fleeting, brief, temporary, short-lived, fugitive, impermanent; Antonym: enduring, lasting, perpetual.
2. biol.
Denoting a plant or animal that completes its life cycle within weeks, days or even hours, eg the mayfly and many desert plants.

1. biol.
Such a plant or animal.