Today, the quintessence of something is the perfect, most typical example of it — the thing that seems to hold the whole idea in one place. ‘She is the quintessence of kindness’ means her kindness is the very heart of what kindness looks like. The word is a little literary; in plain talk people more often say ‘a perfect example’ or use the adjective quintessential.

Today今天，the quintessence of something某樣事物的quintessence（典範） is the perfect, most typical example of it指的是它最完美、最典型的例子 — the thing that seems to hold the whole idea in one place——彷彿把整個概念都濃縮在一個東西上。'She is the quintessence of kindness'「She is the quintessence of kindness」這句話 means her kindness is the very heart of what kindness looks like意思是她的善良就是善良這個概念的核心體現。The word這個字 is a little literary帶點文學氣息；in plain talk在平常說話時 people more often say 'a perfect example'人們比較常說「a perfect example」 or use the adjective quintessential或用形容詞quintessential。

Behind it is an old picture of the world: Earth, Air, Fire and Water were the four known ‘essences’ (here essence means element), and thinkers added a fifth, aether, finer than the rest. Medieval Latin called that fifth essence quinta essentia. English kept the word and slowly moved it from ‘the purest stuff’ to ‘the purest example’.

Behind it這個字背後 is an old picture of the world是一套古老的世界觀：Earth, Air, Fire and Water土、氣、火、水 were the four known 'essences'是當時已知的四種「essence」 (here essence means element)（這裡essence指的是元素），and thinkers added a fifth, aether而思想家們又加上第五種，叫做aether（以太），finer than the rest比其他四種都更精純。Medieval Latin中世紀拉丁文 called that fifth essence quinta essentia把這第五種essence稱為quinta essentia。English kept the word英文保留了這個字，and slowly moved it from 'the purest stuff' to 'the purest example'但意思慢慢從「最純粹的物質」變成「最純粹的例子」。

You may still meet the old ‘fifth element’ sense in history or science writing about Aristotle.

You may still meet你可能還是會遇到 the old 'fifth element' sense「第五元素」這個舊義 in history or science writing about Aristotle在談亞里斯多德的歷史或科學文章裡。