Is 'oniric' English, or is it actually Greek?

'Oniric' is a word borrowed from Greek 'oneiros'.

oniric

(details not available)

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note: The term oniric derives from the Greek word oneiros (dreams or the god of dreams) combined with the suffix -ic. It was borrowed into English perhaps from the French onirique in 1859 to describe something that is dream-like or related to dreams.
Etymology: -

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