What is the origin of the word ‘Petrichor’?

The word “petrichor” conjures up vivid sensory experiences for many: the earthy scent rising from parched soil after a refreshing rain. But what many may not realize is that this evocative term has roots in ancient language and modern science.

Etymological Roots

To delve into the origin of the term “petrichor”, we must first dissect its two components: “petri-” and “-chor”. The word finds its etymological roots in the ancient Greek language:

Petri-: Derived from the Greek word “petra”, which means “stone”. Anyone familiar with the word “petrify” (to turn into stone) will recognize this root.

-Chor: Originates from the Greek word “ichor”, which, according to Greek mythology, is the ethereal golden fluid that flows in the veins of gods, making them immortal.

Taken together, “petrichor” can be loosely translated as “the essence of stone” or “the fluid of stone”, a fitting metaphor for the liquid essence released from earth and stone after a rain.

Scientific Discovery

While the roots of the term reach back to antiquity, the actual coining of “petrichor” is a much more modern event. It was in the 1960s that two Australian scientists, Isabel Joy Bear and Richard Thomas, were studying the causes behind this particular scent of rain. In a paper published in the journal “Nature” in 1964, they introduced the term “petrichor” to describe the distinctive aroma arising from rain falling on dry soil.

Bear and Thomas discovered that the scent was due to a combination of factors. One primary cause was an oil exuded by certain plants during dry periods. This oil would be absorbed by clay-based soils and rocks. When it rained, the moisture caused the oil to be released into the air, producing the characteristic scent. Another component of the scent was identified as geosmin, a metabolic byproduct of certain bacteria known as actinobacteria. Geosmin is responsible for the earthy taste of beets and the scent of freshly turned soil.

The word “petrichor” served not only as a label for the scent but also encapsulated a natural phenomenon that was at once ancient and newly understood. Through the work of Bear and Thomas, humanity gained not just new knowledge but also a new word that bridged the gap between ancient languages and modern science.


The history of the word “petrichor” is a testament to the interconnectedness of culture, language, and science. It draws from ancient mythology and etymology, and yet it is deeply rooted in the scientific exploration of our natural world. The story of petrichor reminds us of the profound human desire to name and understand the beauty and mysteries of the world around us. Every time we use or hear the word, we are not only referencing the aroma of rain-soaked earth but also tapping into a rich tapestry of knowledge and discovery that spans millennia.

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