folk etymology

noun

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

Origin of folk etymology

First recorded in 1880–85

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for folk etymology

Historical Examples of folk etymology

It has sometimes been assumed that most names of this class are due to folk-etymology.
The Romance of Names
Ernest Weekley
This historical connection is most probably due to folk-etymology.
The Romance of Names
Ernest Weekley
But occasionally the results of folk-etymology are literally preposterous.
The Romance of Words (4th ed.)
Ernest Weekley
The companion-ladder on ship-board is a product of folk-etymology.
The Romance of Words (4th ed.)
Ernest Weekley
But the story of Tuna gives no folk-etymology of the name Tuna.
Modern Mythology
Andrew Lang

British Dictionary definitions for folk etymology

folk etymology

noun

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
a popular but erroneous conception of the origin of a word

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012