Twilight is defined by the ancient word twi, which means “half” or “between”.
So twilight is the time between light and darkness.
Dusk is the final stage of twilight and is from the lost English word dox, which meant “dark” or “darker.”
The word “evening” comes from the ancient word “aefen”, meaning “late,” and came to mean the general time between sunset and when you went to sleep.
That’s why we call the end of the day “evening,” and why it’s divided into “twilight” and “dusk”.