It was a pair of scientists, rather than linguists, who coined the word ‘petrichor’ to mean the scent that rain emits when it falls on dry soil. Here’s the story of its origin.

In a scene from the 2001 film Donnie Darko, the titular character sees the words ‘cellar door’ written on a classroom blackboard and asks his teacher what it means. She replies: “This famous linguist* once said that of all the phrases in the English language, of all the endless combinations of words in all of history, that ‘cellar door’ is the most beautiful.”

I think its rhyming sibling ‘petrichor’ has the same pleasant cadence and is certainly one of my favourite words. From the Greek petra meaning ‘rock or stone’, and ichor meaning ‘blood of the gods’, the word aptly describes the enigmatic nature that is the scent of rain as it hits dry earth. For me the scent is most prevalent when a summer storm breaks on hot concrete, an evocative smell that reminds me of all the other times it has happened.

It was a pair of scientists, rather than linguists, who came up with the word – and also investigated the biochemistry around the scent and how it occurred. CSIRO researchers Isabel (Joy) Bear and Richard Thomas co-wrote a paper for Nature magazine in 1964 about the phenomenon: moisture from high humidity and rain fills the pores of earth and rock, which flushes out a particular kind of bacteria called geosmin and releases it as a scent in the air.

Although the scent was not new – in fact, it’s one of the most primal – the pair were the first to give it a name in English that stuck. (It was previously called ‘argillaceous odour’.)

Interestingly, while petrichor is a sought-after fragrance in the perfume world (matti ka attar in India), many people find the taste of geosmin divisive; think the muddy taste of carp or the earthiness of beetroot.

‘Petrichor’ is also one of the common descriptors for pu’er, which us why the fermented tea is considered an acquired taste. Next time you take a sip of sheng or shou pu’er, ask yourself if you can taste rain on dry soil – or the blood of stone.

*That linguist was author JRR Tolkien.