Detailed Instructions: Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
See one example below:
Problem: How are i.e. and e.g. pronounced?
Solution: i.e. stands for id est (Latin), which means 'that is'. You use it to link in a deeper explanation about something. Pronounce it 'eye - ee'. e.g. stands for exempli gratia (also Latin), which means 'for example'. You use it to link in an example of a more generic term. Pronounce it 'ee - jee'
Explanation: Perfect answer because it's consistent with context uses required information from the question to provide the detailed answer with an example.

Problem: This is a question for English wordsmiths. Is there a word that 'feels' like the word 'ethereal' that means something ethereal that quickly disappears. Or is 'ethereal' the correct word choice for this? Ethereal was the first word that popped into my head for this. From the various definitions that I've looked at for ethereal, it says delicate, beautiful, heavenly, etc. but not necessarily quickly vanishing, except for the secondary definitions related to ether that suggests it evaporates. I'm just wondering if there is a better word than this. I'm using the term 'ethereal skill' to describe a certain type of pilot skill (instrument flying) that requires tremendous practice to achieve proficiency, and once proficiency is achieved it is a beautiful thing, but if you don't practice it regularly, that skill vanishes after a few weeks. USAGE: Instrument proficiency is an ethereal skill that once obtained must be maintained through constant and regular practice.
Solution:
You are probably looking for the word ephemeral. ephemeral: Lasting for a very short time.