Not sure why the downvote or what is so ridiculous about the names. Other than "full size" they are all clear in meaning and all are easily remembered. Europe has many things on us but I'm not sure a series of arbitrary numbers is a better naming scheme than ours.

Also, all I was saying to begin with is that we don't actually have an issue with fitted sheets not fitting. Or at least I've not experienced that. I've had a few mattresses of varied sizes. I've also primarily bought cheap/affordable sheets.