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"The hypnagogic state is that heady lull between wakefulness and sleep when thoughts and images flutter, melt, and transform into wild things," wrote Boston Globe correspondent Cate McQuaid (October 1, 1998). Some scientists have attributed alien-abduction stories to this state, but for most people these "half-dreams" are entirely innocuous. Perhaps the most famous hypnagogic dream is that of the German chemist Friedrich August Kekule von Stradonitz, who was inspired with the concept of the benzene ring by a vision of a snake biting its own tail. You're not dreaming if the Greek root "hypn-," meaning "sleep," seems familiar - you've seen it in "hypnotize." The root "-agogic" is from the Greek "-agōgos," meaning "inducing," from "agein" meaning "to lead." We borrowed "hypnagogic" (also spelled "hypnogogic") from French "hypnagogique" in the late 19th century.

: of, relating to, or occurring in the period of drowsiness immediately preceding sleep

Examples

"People who play lots of computer games sometimes experience 'screen dreams' as they fall asleep, in which they see vivid images of the game they have been playing. These screen dreams are also products of the hypnagogic state." - From Paul Martin's Counting Sheep, 2002

"These hallucinations, called hypnagogic hallucinations, may occur when falling quickly into REM sleep, as you do when you first fall asleep, or upon waking." - From an article by Jeff Barnet in the Las Cruces Sun-News, January 11, 2011