Hypnosis

google

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late 19th century: from Greek hupnos ‘sleep’ + -osis.

wiktionary

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Derived from hypn(otic) +‎ -osis(“state”, “condition”, nominal derivational suffix).

etymonline

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hypnosis (n.)

1850, "the coming on of sleep," coined (as an alternative to hypnotism) from hypno- "sleep" + -osis "condition." But the distinction was not sustained, and by 1876 hypnosis was being used of artificially induced conditions.