Eggcorn is a term invented on a blog called Language Log in September 2003. Mark Liberman wrote an article about a woman who always called an acorn an eggcorn (which, although technically wrong, has a certain relevance and beauty about it) and Geoffrey Pullum suggested that eggcorn should be the term for this sort of wise mistake.
An eggcorn is a bit like a pun, except that the speaker doesn't know he's making it. An eggcorn is also a bit like a malapropism, except that the result is interesting and wise.
I think we should embrace the eggcorn. I mean, I've never thought that language should be put on a pedastool, though I can't agree that there should be no holes barred, or that we should be able to give completely free range to our tongues. No, we do need to keep on the straight and arrow to a large extent, even though the nature of communication is such that the lame man is bound to be affected by his ethnic routes, which have been travelled since we first acquired our posable thumbs, so that many changes are constantly being made and lots are now a fate accompli.
But what a joy it is, nevertheless, to imagine an ex-patriot watching a preying mantis as he pours his breakfast skimp milk.
Word To Use Today: eggcorn. This is a nice new word. Enjoy it!