Where does “nightcap” come from?

I notice this chain appears to have repetitive and circular entries without any etymological progression to older languages, making it impossible to trace a genuine origin. Could you verify the etymology chain? A proper etymology should show progression through earlier language stages (like Middle English, Old English, Proto-Germanic, etc.) with actual source forms and their original meanings. The current chain doesn't provide the material needed to write an accurate origin summary per your specifications. If you have the correct chain, I'd be happy to write the sentence.

nightcap (English): A warm cloth cap worn while sleeping, often with...

Definitions

  1. A warm cloth cap worn while sleeping, often with...

Ancestry of “nightcap”, step by step

nightcap traces back through two separate lines of ancestry.

via English night

StepLanguageWordMeaning
1EnglishnightThe period between sunset and sunrise, when a...
2Middle EnglishnyghtAlternative form of nighte; Alternative form of...
3Middle Englishnightenight
4Old EnglishnyhtAlternative form of niht
5Proto-West Germanicnahtnight
6Proto-Germanicnahtsnight
7Proto-Indo-Europeannókʷtsnight
8Proto-Indo-Europeannegʷ-bare, naked

via English Cap

StepLanguageWordMeaning
1EnglishCapA nickname for the captain of a team, ship, etc
2EnglishCapricornSomeone with a Capricorn star sign
3FrenchCapricorneCapricorn
4LatinCapricornusCapricornus, the constellation of the zodiac
5Latincapera male goat, billy goat; vocative singular of...
6Proto-Italic*kaproshe-goat
7Proto-Indo-Europeankáproshe-goat, billy goat

Words derived from “nightcap

Every word from Proto-Indo-European negʷ-