久旱之后，第一场雨落在干土上升起的那股气味。 The pleasant smell that frequently accompanies the first rain after a long period of warm, dry weather.
The pleasant smell that frequently accompanies the first rain after a long period of warm, dry weather. 久旱之后，第一场雨落在干土上升起的那股气味。
词源etymology
希腊语 petra（石）＋ ichor（ἰχώρ）。 ichor 在希腊神话里是流淌在诸神血管中的东西——神不流血，流的是 ichor。 所以这个词字面是：石头里流出的神血。
Greek petra (stone) + ichor (ἰχώρ) — in Greek myth, the fluid that runs in the veins of the gods; gods do not bleed blood, they bleed ichor. So the word literally means: the blood of gods, run out of stone.
背景the story
1964 年，澳大利亚 CSIRO 的两位矿物化学家 Isabel Joy Bear 与 Richard Grenfell Thomas 在《自然》杂志上 共同为这股气味命名（论文题为 Nature of Argillaceous Odour，1964 年 3 月 7 日刊出）。 在那之前，它在学术文献里只有一个乏味的名字：「黏土气味」。
他们在论文里给出了气味的一半来源：干旱期里植物分泌的油脂被岩土吸附，雨点砸下时把它重新释放到空气中。 后来的研究补上了另一半：土壤放线菌产生的 geosmin（土臭素）——浓度低到十亿分之 0.4，人的鼻子仍闻得到。
一个由化学家在论文里造的词，如今是英语里最常被引作「诗意」的词之一，并且进了词典。 造词能不能活下来，与它诞生在实验室还是诗里无关。
In 1964, two Australian CSIRO mineral chemists — Isabel Joy Bear and Richard Grenfell Thomas — named the smell in Nature (the paper, Nature of Argillaceous Odour, ran on 7 March). Until then the literature had called it, drably, “argillaceous odour” — clay smell.
Their paper supplied half of the answer: oils exuded by plants during drought are absorbed by rock and soil, and the rain flings them back into the air. Later work added the other half — geosmin, made by soil actinobacteria, which the human nose can pick out at 0.4 parts per billion.
A word coined by chemists in a journal is now one of the words English most often calls “poetic” — and it made the dictionaries. Whether a coinage survives has nothing to do with whether it was born in a laboratory or a poem.
中文里的邻居neighbors in chinese
「雨腥味」「土腥气」——意思对得上，气质对不上。 中文这两个说法偏中性，甚至略带嫌恶；而 petrichor 自带雅意。 指同一件事、但褒贬相反，这种错位恰恰是翻译最难的地方。
雨腥味 (“rain-fishy smell”) and 土腥气 (“earthy-fishy smell”) name exactly the same thing and miss the register: both lean neutral-to-faintly-put-off in Chinese, while petrichor arrives dressed for poetry. Same referent, opposite valence — precisely the mismatch that makes translation hard.
The diverse nature of the host materials has led us to propose the name "petrichor" for this apparently unique odour which can be regarded as an "ichor" or "tenuous essence" derived from rock or stone.鉴于宿主材料的多样，我们提议将这种看来独一无二的气味命名为 petrichor——可视作一种从岩石中渗出的「灵液」或「稀薄的精华」。（命名那一句的中译） Isabel Joy Bear & Richard Grenfell Thomas Isabel Joy Bear & Richard Grenfell Thomas · Nature of Argillaceous Odour, Nature 201 Nature of Argillaceous Odour, Nature 201 · 1964
It means the smell of dust after rain. — What does? — Petrichor. — But I didn't ask. — Not yet. But you will.「它的意思是，雨后尘土的气味。」「什么的意思？」「Petrichor。」「可我没问啊。」「还没问。但你会问的。」（中译） Neil Gaiman Neil Gaiman · Doctor Who, "The Doctor's Wife" Doctor Who, "The Doctor's Wife" · 2011
The first storm in six weeks broke at dusk, and the whole street came out for the petrichor. 自拟例句 our own example, not a quotation Petrichor rose off the tarmac before the rain even arrived, the way a room changes just before an argument. 自拟例句 our own example, not a quotation The estate agent opened every window an hour before the viewing and let the petrichor do the selling. 自拟例句 our own example, not a quotation 词典词，正式写作可用。 属于低频高雅词，写景时很有效—— 但一篇文章里用一次就够，第二次就成了炫技。
A dictionary word — safe in formal writing. Low-frequency and elevated; excellent in scene-setting. Once per essay is enough. The second time is showing off.