Folk etymology

Many English folk etymologies involve backronyms.

It is not improbable that, in some locality where tram-roads were a novelty, their name may have been associated in folk-etymology or by pre-scientific etymologers with that of the engineer.

He even sharked up a false or "folk" etymology in which saunter is made to derive from sainte terre, making the saunterer a crusader.

SURCEASE owes its form and meaning to a remarkable folk-etymology, as has been pointed out by Prof. Skeat:—"It is obvious, from the usual spelling, that this word is popularly supposed to be allied with cease, with which it has no etymological connexion."

Thus hamburger (whose true etymology is 'city of Hamburg' + er 'someone from') has been reanalyzed as ham + burger 'burger made with ham.' [...] Subsequently, on the analogy of this folk etymology, new forms such as cheeseburger, chiliburger, and plain burger have been created.