Getting it wrong so often as to be right

University of Pennsylvania's  Language Log reports that the single most authoritarian source of English words, the Oxford English Dictionary, has added the word "eggcorn" as a variant of "acorn" since misuse has become so entrenched that the misused word is the embodiment of a whole category of misuses.

As early as 1844, people were reinterpreting the word “acorn” as “eggcorn”, either deliberately, for humorous purposes, or in all innocence, in a struggle to analyse, in a way that made sense to them, what the word’s spelling must be: acorns are, after all, seeds which are somewhat egg-shaped, and in many dialects the formations acorn and eggcorn sound very similar. Since 2003, it has become a widely accepted term for this category of words as a whole, appearing in books and journals, and on the internet, often alongside its musical sibling, the mondegreen or misheard lyric (which first appeared in the OED in 2002). As such, it has now become an autological word: one which belongs to the category it describes.