folk etymology

American  

noun

1. a modification of a linguistic form according either to a falsely assumed etymology, as Welsh rarebit from Welsh rabbit, or to a historically irrelevant analogy, as bridegroom from bridegome.

2. a popular but false notion of the origin of a word.

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folk etymology British  

noun

1. the gradual change in the form of a word through the influence of a more familiar word or phrase with which it becomes associated, as for example sparrow-grass for asparagus

2. a popular but erroneous conception of the origin of a word

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Etymology

Origin of folk etymology

First recorded in 1880–85