Word of the Day


A pleasant smell that frequently accompanies the first rain after a long period of warm, dry weather

Warm summer rain can be a delight, as can the ‘petrichor’, the pleasant earthy smell that rises up from soil and undergrowth when the rain stops and the sun comes out.

The word first appeared in print in 1964 having been created by two scientists, Richard Thomas and Joy Bear, who needed a name for the phenomenon to use in an article about their research in the journal Nature. They constructed the word ‘petrichor’ from the Greek petra, meaning stone, and īchōr, a fluid that was said to flow through the veins of the gods of Greek mythology.

In the Nature article, the researchers explained how the unique scent comes from an oil that some plants exude during periods of dry weather. That oil is absorbed into stones and soil that are clay-based. The oil is subsequently released into the air when it rains, along with geosmin, a by-product of actinobacteria. The two combine to create the ‘petrichor’.


a pleasant smell that frequently accompanies the first rain after a long period of warm, dry weather

Other than the petrichor emanating from the rapidly drying grass, there was not a trace of evidence that it had rained at all.

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Macmillan Dictionary

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