Folk Etymology

Folk etymology is the process by which speakers reanalyze an unfamiliar word into familiar-looking parts and reshape it to match. Crayfish is Old French crevice, pulled toward fish. Muskrat is an Algonquian word pulled toward musk and rat. Hangnail is Old English angnægl, where ang meant painful and nothing hangs; shamefaced was shamefast, fixed in shame. The visible parts are the result of the mistake, not the source of the word.

Related mechanisms move word boundaries. Back-formation invents a shorter word by stripping what looks like a suffix: edit from editor, burgle from burglar. Rebracketing shifts the article — a napron became an apron, an ewt became a newt. Pea comes from pease, a mass noun mistaken for a plural. Spelling was interfered with too: island is native igland, respelled on the false model of Latin insula. The pressure throughout is toward legibility, the same instinct Plain Language serves deliberately.

The appetite for legible origins also produces stories that are themselves inventions. Posh is not "port out, starboard home", golf is not an acronym, and rule of thumb has no documented link to a law about beating a wife; acronymic origins for words older than the twentieth century are almost always retrospective. The Metasyntactic Variable foo is a partial case worth separating out: the word appears in 1930s comic strips and so predates the army acronym FUBAR often credited with producing it, even though the pairing with bar probably was shaped by the acronym. These are textbook Plausible Mechanism: tidy accounts with no Provenance, spreading because they beat the honest answer of "origin unknown".

The lesson generalizes past words. Visible internal structure is evidence about what speakers expected, not about where a thing came from — an Anchoring Effect made of morphemes, and one that applies to Naming as much as to etymology. Dated attestation, not plausibility, is the test.