What's an eggcorn?

Had never heard of this, but pretty cool....

In linguistics, an eggcorn is an idiosyncratic substitution of a word or phrase for a word or words that sound similar or identical in the speaker's dialect. The new phrase introduces a meaning that is different from the original, but plausible in the same context ("old-timers' disease" for "Alzheimer's disease"). This is as opposed to a malapropism, where the substitution creates a nonsensical phrase. Classical malapropisms generally derive their comic effect from the fault of the user, whilst eggcorns are errors that exhibit creativity or logic.[1] Eggcorns often involve replacing an unfamiliar, archaic, or obscure word with a more common or modern word ("baited breath" for "bated breath").[2]

http://http://en.wikipedia.org/wiki/Eggcorn