Pronunciation: /ˈpɛtrɪkɔːr/ Part of speech: noun Definition: The distinctive, earthy, and usually pleasant scent that rises when rain falls on warm, dry soil. Etymology: <cite index="6-2,6-3">The word was coined in 1964 by Australian scientist Richard Thomas, in a paper co-authored with Isabel Bear, and was derived from Ancient Greek *pétra* ("rock" or "stone") and *ikhōr* (ichor), the ethereal fluid said to be the blood of the gods in Greek mythology.</cite> <cite index="8-4">For years before the coinage, scientists had simply called the phenomenon *argillaceous odor*, because it was particularly noticeable near soil rich in whitish clay.</cite> Synonyms: after-rain scent, geosmin, argillaceous odor, pluvial aroma, earthy fragrance, rain smell In a sentence: She stepped off the porch just as the summer storm passed, drawing in a long breath of pure petrichor_ that clung to the still-warm sidewalk.