Informal names given to people, often shorter or based on their appearance or personality, used instead of or in addition to their real name.
From 'an ekename' (Middle English), where 'eke' meant 'also' and 'name' meant 'name'—literally an 'also-name.' The 'n' shifted over time from 'eken' to 'nicken.'
This is a case of rebracketing gone wrong—people heard 'an ekename' and thought it was 'a nickname,' and that mistake stuck permanently in the language!
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