IPA: /ˌɔːtəʊˈhaɪpnəʊsɪs/
KK: /ˌɔːtoʊˈhaɪpnoʊsɪs/
A state of hypnosis that a person brings about in themselves, often used for relaxation or self-improvement.
She practiced autohypnosis to help manage her stress levels.
Autohypnosis is formed from "auto-" (meaning self) and "hypnosis" (from Greek "hypnos", meaning sleep). The word refers to a state of sleep or trance that one induces in oneself.
Think of 'self' ('auto-') inducing a state of 'sleep' ('hypnos') — that's what autohypnosis means.