astronomical twilight
noun
either of two periods of partial darkness, after sunset or before sunrise, when the center of the sun is more than 6° but less than 18° below the horizon.
Words Nearby astronomical twilight
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use astronomical twilight in a sentence
The sun, creeping from 18 to 12 degrees below the horizon, is working its way through astronomical twilight.
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