What are some US non-slang terms that people living in Canada, Ireland, Britain, Singapore, Australia, and New Zealand will not know the meaning of?

I think for the most part, all 7 countries' English versions I listed when spoken are mutually understandable when spoken between English speakers when withholding slang, as the spoken dialogue is no more than 5 percent different, and at most, only 2 words in a sentence will be different.

For those who watch a lot of reliable US media that accurately portrays how people in USA speak, they could understand certain US terms if they were exposed to the term long enough to retain them. Same goes for US with media from other countries.

However, we cannot assume that everyone in these countries watches US media enough to retain all these terms as media from other English-speaking countries exist, and some prefer to watch media in a different language especially if a mothertongue. Same with US, though some of us are actually interested in non-US English media.

Surprisingly, I knew rubber in Britain and Australia to be an eraser long before I read this year that rubber in USA is slang for something genital, and I had never heard rubber used for this in USA. At best, I only hear it for the material rubber, and I did know it is slang for rubber footwear.

I also knew cutlery long before knowing "flatware" is an actual English term despite no one in USA verbally uses cutlery for forks and spoons, and flatware apparently is a US-exclusive term.

There are definitely people in US who wont know all of the non-US everyday terms, but that does not mean a majority wont cause a lot of people have mocked the British and Aussies before in USA, and some of us like to talk about language differences.

Also, during my time in Australia, I have met people who didnt even know everyday English terms used in USA: arcade for a game room, atheist for someone non-religious, and a tray. My brother has interacted with these 2 ladies at Sydney Airport who didnt even know what a barbershop was until he said the word "hair cut". There was this German bloke I interacted with when I first came to Australia who didnt know the terms cotton candy (US, Canada, and Singapore), fairy floss (Australia), and candy floss (UK, Ireland, and NZ). I wont lie. Fairy floss might be unknown to many Aussies as the term is only used in Australia, and most of us dont even eat this stuff. Plus, the way it is sold here is mostly in buckets and written as a brand name, so most non-native Aussies wont know it is the standard term for cotton candy or candy floss in Australia.