Definition of "hypnagogic" [hyp•na•gog•ic]

• Inducing sleep; soporific. (adjective)
• Of, relating to, or occurring in the state of intermediate consciousness preceding sleep: hypnagogic hallucinations. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Because the existing word hypnagogic means “of, relating to, or occurring in the state of intermediate consciousness preceding sleep,” and hypnopompic means “of or relating to the partially conscious state that precedes complete awakening from sleep,” many people came up with hyp - coinages."
• "As to her own ordeal, Henry told her there was a name for the strange, shifting images you see just before sleep: they were called hypnagogic hallucinations, and they often occurred in connection with sleep paralysis."
• "The hallucinations produced in this way are called hypnagogic (from its derivation this term is properly applied only to phenomena observed at the instant when we fall asleep, or when we are imperfectly awakened, and not to the period of most perfect repose), and they occur when the subject is not in a condition favorable to sound sleep."