Affixes

The adjective hypnagogic (or hypnogogic) refers to the semiconscious state immediately before falling asleep (Greek agōgos, leading to); its opposite is hypnopompic (Greek pompē, sending away); in medicine, a hypnotic is one of a class of drugs that induces sleep; hypnopaedia is learning by listening to recordings during sleep.

Hypnosis is a trance-like state that resembles sleep, induced by the monotonous repetition of words or gestures. Some terms in hypno‑ refer to the state: hypnogenesis is its induction, and hypnotherapy is its use as a therapeutic technique; hypnotic can also be an adjective relating to this state, or to something compelling or soporific.