The letter Thorn. Or Þorn.
Which is probably why
nobody uses it any more.I put something odd in my new book way back when I was writing the first draft, and forgot to check whether or not it works when you look at it on a Kindle. And joy of joys - it does!

May I introduce... the letter Thorn!

You see, the English language has a long and messy history, both in its spoken and written versions. The alphabet we know, love, and wish-we-could-get-that-damn-song-out-of-our-heads used to be somewhat diff...