'autohypnotism' originates from Greek prefix 'auto-' (from Greek 'autos' meaning 'self') combined with 'hypnotism' (from Greek 'hypnos' meaning 'sleep', via French/Latin).

'autohypnotism' was formed in English by combining 'auto-' + 'hypnotism' (with 'hypnotism' itself coined in the 19th century from Greek 'hypnos' via French); related formations include 'autohypnosis' and later back-formed or extended to 'autohypnotism'.

Initially the components referred to a 'self-induced sleep-like state'; over time the term came to mean a self-induced hypnotic state or technique for influencing one's own mental state (not necessarily literal sleep).