By accident or in error; incorrectly thinking or believing something that is not true.
From 'mistake' (Old Norse 'mistaka': 'mis-' wrongly + 'taka' to take), meaning to take wrongly or misunderstand. The adverb form adds '-ly' (Old English origin) to make an adjective into an adverb, appearing in English by the 1500s.
Mistakes and errors are so important to how brains learn that neuroscientists actively study them—your brain learns more from mistakes than from correct answers! That's why struggling with hard problems actually builds stronger memories.
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