One of the curses of life today was outlined by the Times in 2013: “Modern alarm clocks destroy dreams because they rip you through your hypnopompic sleep state so fast.”
The hypnopompic state is that drowsy, half-alert, comfortable state you’re in as you awaken slowly and naturally. It’s the opposite of the one you drift into as you gradually fall asleep, which is the hypnagogic state.
Both words derive from Greek hupnos, sleep. Hypnopompic combines it with pompē, sending away, while hypnagogic adds agōgos, leading. The former was coined by Frederic Myers, a philologist and one of the founders of the Society for Psychical Research, while the latter was the creation of Alfred Maury, a French researcher into dreams. Hypnagogic came into English from French hypnagogique. Though it’s conventional to lose the final o from prefixes like hypno- when they’re put before a vowel, many users spell the word hypnogogic. That may be because hypna- is very rare in English (the only other in the Oxford English Dictionary is hypnaesthesia, which in any case is now often spelled hypnesthesia) and they’re swayed by all the others beginning hypno-. And few people now know the Greek root begins with a vowel.
The terms are most often applied to hallucinations during these states that seem completely real to their subjects. They may hear music or their name being called or see images of people. Repeated or particularly vivid episodes may lead some to fear that they’re mentally ill. Such hypnagogic or hypnopompic experiences turn out to be common, though the former occur more often. It’s thought that some reports of ghosts come from such experiences.