I just learned a new word—eggcorn—that I expect to use a lot. 'Eggcorn' is to language in general what 'mondegreen' is to lyrics. It stems from someone's misspelling (and probably mispronunciation and misunderstanding) of 'acorn'—just as 'Lady Mondegreen' was a mistake for 'laid him on the green'.

'Eggcorn' was coined as a general term for this type of mistaken usage by the people who write the blog Language Log. Now the eggcorn has its own web site: The Eggcorn Database.

Happy browsing!

Of course, you can post your favorite eggcorns here.

I'll start with 'copywrite' for 'copyright'.