Folk etymology

Folk etymology (also known as spook etymology and popular etymology) is an "explanation" of the meaning of a word based on its superficial similarity to other words, without analysing its morphological structure, documented history or scientifically reconstructible past forms. Of course if one does take such things into account, the result is a scholarly etymology.

Folk etymology may make people change the form of a word so that it would better match its popular rationalisation. For example, Old English sam-blind 'half-blind' became sand-blind (as if 'blinded by the sand') when people were no longer able to make sense of the element sam 'half', and Old English bryd-guma 'bride-man' became bridegroom after the loss of the Old English word guma 'man' rendered the compound semantically obscure. More recent examples are French (e)crevisse which became English cray-fish or asparagus which became sparrow-grass.

The pantry is not so called since it is or was used for storing pots and pans, but because it was originally a bread store (Old French paneterie). (Room; see reference below)

In non-sexist language, folk etymology is one source of neologisms like herstory to replace history.

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Reference

Adrian Room, Dictionary of True Etymologies, 1986, Routledge & Kegan Paul