The mistery is solved!

I'm American and I have never seen anyone spell it "mistery"

We don't spell it that way

I apologise, then. I didn't know it could be spelt two different ways

Well according to the Merriam Webster dictionary, somebody spells it that way. (I posted the link and everything!)

the only Dictionaries that are the norm, are the Oxford, original Queen's English, and Webster's, American butchered English, where Merriam came in, i don't know. but to get a 14 day free membership for a dictionary website? that's completely new!

Merriam-Webster is the same as Webster's. I agree that it's unusual to have a membership, but the copyright is there.