Criteria vs. Criterion

I made a mistake in 5B today when I said that criteria was singular and criterion was plural. It's the opposite. Criteria is plural.

I was curious about my confusion so I looked at the Webster definition on-line which explains that Americans use criteria for both singular and plural meaning! That's why I said they both sound the same to me. In fact, I don't think I've ever heard anybody use the word criterion.

Of course this all makes sense to me now, because LEAP was written by Canadians, not Americans. If an American had written the book, they probably wouldn't have used the word criterion!

I'm not the ruler of the English language, but I think you will be safe in America if you only use the word criteria. However, I will check with Greg just to play it safe :D

So....
What is the criteria by which we judge the restaurant? (SINGULAR)
I have three criteria that my future husband must meet in order for me to marry him. (PLURAL)