petrichor

noun

pe·​tri·​chor ˈpe-trə-ˌkȯr 

: a distinctive, earthy, usually pleasant odor that is associated with rainfall especially when following a warm, dry period and that arises from a combination of volatile plant oils and geosmin released from the soil into the air and by ozone carried by downdrafts

Australian scientists first documented the process of petrichor formation in 1964 …

—Tim Logan

The intensity of the petrichor smell can vary with the type of soil and how heavily the rain is falling.

—John Boyer

Examples of petrichor in a Sentence

Recent Examples on the Web

This is called the petrichor effect, which occurs when the smell of rainfall triggers memories or emotions. —Alyssa Hui, Verywell Health, 19 Apr. 2024

Australian scientists first documented the process of petrichor formation in 1964 and scientists from the Massachusetts Institute of Technology further studied the mechanics of the process in the 2010s. —Tim Logan, Discover Magazine, 28 Aug. 2018

Scientists have named the aroma petrichor. —Roger Naylor, The Arizona Republic, 16 Mar. 2023

Could Titan have its own petrichor too? —Marina Koren, The Atlantic, 14 June 2021

Rain on pavement smells different from rain on trees, but the collective term for the resulting odor is petrichor. —Avery Hurt, Discover Magazine, 24 Feb. 2021

The wine is packed with aromas and flavors of lime zest, blood orange slices, Bees Knees Salted Honey and petrichor, a fragrance that reminds many of a cross between ozone and the wet concrete surrounding a swimming pool in the summertime. —Michael Alberty | For The Oregonian/oregonlive, oregonlive, 15 Feb. 2022

In drought the rains will come when the sweet scent of sage meets the smell of petrichor that heralds an incoming storm, and a night sky of stars holds our humility and wonder as the Milky Way arches over us. —BostonGlobe.com, 7 Apr. 2021

Smells like wool, leather, animal soap and petrichor—the bloom of rocks after rain—rarely impinge, either. —Sam Kean, WSJ, 22 Oct. 2020

Word History

Etymology

petr(o)- + ichor

Note: The word was introduced by the Australian mineral chemists Isabel Joy Bear (born 1927) and Richard Grenfell Thomas (†1974) in "Nature of argillaceous odour," Nature, vol. 201, No. 4923 (March 7, 1964), pp. 993-95. According to the authors, "The diverse nature of the host material 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."

First Known Use

1964, in the meaning defined above

Kids Definition

petrichor

noun

pe·​tri·​chor

ˈpe-trə-ˌkȯr

: an earthy odor that is associated with rainfall especially after a warm and dry period