from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang An alcoholic beverage that is surreptitiously altered to induce diarrhea or stupefy, render unconscious, or otherwise incapacitate the person who drinks it.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. an alcoholic drink doctored with a drug intended to quickly render the drinker unconscious.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. slang term for knockout drops
Probably after a notorious Chicago bar shut down in 1903, allegedly because its customers were served spiked drinks and then robbed.(American Heritage® Dictionary of the English Language, Fourth Edition)
Probably named for the manager and bartender of a Chicago establishment, the Lone Star Saloon and Palm Garden Restaurant, which operated from 1896 to 1903, who was accused of using "knockout drops" to incapacitate and rob some of his customers. (Wiktionary)