Plural of aurora; multiple natural light displays in Earth's atmosphere, such as the northern lights or southern lights.
From Latin aurora 'dawn' or the Roman goddess of dawn, plus English -s plural. This English pluralization has been standard since the term entered scientific English.
The fact that we call them after the Roman goddess of dawn shows how old the aurora observations are—humans have been watching these lights for thousands of years, long before we understood they come from the sun.
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