Eggcorn

An eggcorn is a substitution that replaces part of a fixed phrase with something that sounds the same and still makes its own kind of sense — "for all intensive purposes" for "for all intents and purposes", "old-timers' disease" for "Alzheimer's disease". The name has two authors: Mark Liberman posted the original case on Language Log in September 2003 — a writer's egg corn for acorn — and observed that the error type had no name, and Geoffrey Pullum supplied "eggcorn". The substitution is a reasonable guess: acorns are egg-shaped, corn once meant any small hard grain, and in some dialects, as Liberman noted, the two are near-homophones, which makes it a mishearing rather than only a misspelling.

The definition hinges on what survives the swap: a working semantic logic the speaker arrived at independently, the same reasoning Prototype Theory describes for ordinary categorization — matching an unfamiliar part to the nearest thing that already makes sense. That separates the eggcorn from a malapropism, where a similar-sounding word is substituted with no logic of its own — a category named after Mrs. Malaprop in Sheridan's The Rivals (1775), whose own name comes from French mal à propos. It also separates it from Folk Etymology, a substitution the whole speech community adopts into the standard form over historical time; an eggcorn is usually one speaker's live reanalysis that may never become the norm. It sits beside the Malaphor, a blend of two idioms rather than a reanalysis of one, and the Mondegreen, the same mechanism applied to a whole misheard line, in a small Taxonomy of substitution errors.

What makes the eggcorn worth naming separately is that it is evidence of reasoning, not its absence. The speaker has parsed an opaque idiom into parts, found one obscure, and swapped in a part that resolves the obscurity — the same Plausible Mechanism that drives folk etymology at word scale. Its Provenance is always recoverable to a sensible guess, which is what makes eggcorns collectible rather than merely wrong, and why the right comparison is a word's Ground Truth meaning, not what sounds nearly right.