Land of Nod is the name of the land, to "the east of Eden," to which Cain was banished after murdering his brother Abel in the first book of the Bible. The word "nod" means "wandering."

"So Cain left the Lord's presence and settled in the land of Nod." (Genesis, chapter 4, verse 16)

The term has more recently been associated with being asleep and was supposedly first used in this context in print by Jonathan Swift in his A Complete Collection of Genteel and Ingenious Conversation (1738).