Where did this term originate from? According to Etymonline.com, it originates from O.E. eaca, which means to "increase". However, I can't see how the "n" got stuck in there too.
Does anyone have any relevant information?
The regular outcome of OE eaca would be ick, as in ickname. At some point an ickname became reanalyzed as a nickname, and that's how the word has reached us today.
A more natural, and logical guess by backward extrapolation would be based on nick rather than ick/ eace:
nick: a short cut, a notch. Hence 'nickname', a short name.
Nick: the devil. Whence, apart from the actual name, an endearing term for that little devil, a 'nickname'.
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