Evanescent
Lasting only a very short time; fleeting, and already on the edge of imperceptibility — and also a hard technical term in physics and mathematics for a quantity that decays rather than propagates.
Full definition of Evanescent →:: COMPARE ::
EvanescentvsEphemeral
The short answer
Ephemeral is about DURATION — it lasts a day. Evanescent is about PERCEPTIBILITY — it is fading out of your senses as you watch. A mayfly is ephemeral; a scent leaving a room is evanescent.
Side by side
| Aspect | Evanescent | Ephemeral |
|---|---|---|
| Concerns | Perception | Duration |
| Measured in | Detectability | Time |
| Technical use | Physics, calculus | Biology, collecting |
| First English sense | 1717 | 1560s |
What each one means
Ephemera
Things made to be discarded that survived anyway — tickets, menus, posters, handbills. More broadly, anything of transitory existence; in zoology, a mayfly.
Full definition of Ephemera →