the.com/firstlight
The day's opening handshake, when darkness blinks first and the sky admits defeat.
means The earliest daylight at dawn, just before sunrise, when the sky brightens but the sun hasn't cleared the horizon.
from A plain old English welding of first and light, dating back centuries; sailors and farmers timed their lives by it long before alarm clocks existed.
Astronomy termA telescope's first image is its firstlight.
Before sunriseLight arrives earlier than the sun itself.
Military favoriteOperations love launching at firstlight's cover.