Other forms: nightcaps
A nightcap is a last drink taken before bed. Have a nightcap, one final nightcap, a nightcap of whisky.
The literal one was a cloth cap worn in bed when houses were cold, which is where the drink took its name. Alcohol before bed brings sleep on faster and wrecks the second half of the night, which the habit ignores.
1nounnightcapA last drink taken before bed.
“Before bed, he poured himself a small whisky as a nightcap.”
nightcap is a drink.
Night plus cap, from the cap worn in bed, with the drink sense taken from it.
From night + cap.
Etymology from Wiktionary, CC BY-SA