Noun - a plant with a very short life cycle.
Origin - from the Greek ephemeros: lasting only a day.
Derivatives - ephemerality, ephemerally and ephemera.
I produced the most amazing piece of ephemeral art ever created. Oh, you must have missed it.
My liking of 'ephemeral' stems from the concept behind it. I like things that only last long enough for your appreciation not to diminish. Some examples are sand castles, snow men and pieces of origami that you screw up and throw away as soon as the novelty wears off. There is nothing more satisfying than building a great big sand castle (yes, I may be 29 but I still take my bucket and spade to the beach) and then kicking it in at the end of day.
As much as I like the sound of the word... actually, now that I have written and read it a few times, my admiration is beginning to wear off quite quickly. It is starting to sound like 'effeminate' and the spelling actually quite annoying. Shame, but I guess that is the nature of the thing.