any spasm that accompanies the transition to sleep ; also spelled hypnogogic jerk , myoclonic jerk
noun, Psychology. 1. the drowsy period between wakefulness and sleep, during which fantasies and hallucinations often occur.
hypnagogue hyp·na·gogue (hĭp’nə-gôg’) n. A drug or an agent that induces sleep.
hypnapagogic hyp·nap·a·gog·ic (hĭp-nāp’ə-gŏj’ĭk, -gō’jĭk) adj.
hypnesthesia hyp·nes·the·sia (hĭp’nĭs-thē’zhə) n. See drowsiness.