That chimes with my experience in the UK.

I personally call ( ) "round brackets" to try and be a bit more explicit about which kind of bracket I mean, but I don't think that's a very common turn of phrase. Similarly I've picked up calling { } "brace brackets" from programming.

I heard it (in UK) referring to { }.

In programming circles I've come to expect: () parens, [] brackets, {} braces. Probably easier if we all try to stick to that.

Yes, as someone who lives in the UK I call () parenthesis, [] square brackets and {} curly braces to make it (somewhat) clearer. I pronounce root and route differently for the same reason. But I'm a foreigner so I can take some liberties :)

This also in the US, and < > as elbow brackets.

> in school I don't think I ever heard the word "parentheses" used to refer to (), or at all for that matter.

Only in maths or ever?

The word parentheses is very rarely used in Britain.

(Brackets), [square brackets], {curly brackets or braces} and <angle brackets> are the terms used in all fields, maths and normal life included.