Petrichor
Etymology
Coined in 1964 by two Australian scientists, Bear and Thomas, in the journal Nature, for the oil that plants release and soil absorbs in dry weather. From Greek petra, "stone," + ichor — in Greek myth, the ethereal fluid said to flow in the veins of the gods. Literally, "the blood of the stone."
noun · /PET-rih-kor/
The earthy, pleasant smell of rain falling on dry ground.
What it names
The precise sensory event you’ve noticed a hundred times and never had a word for — the scent of the first rain after a dry spell.
Example
She opened the window for the petrichor rising off the hot pavement after the storm.
Related idea
The specific rainy-air smell also owes a lot to geosmin, a compound our noses detect at astonishingly tiny concentrations.