you know, there are a surprising number of things that are just normal British things that we thought were just things JK Rowling made up for the wizarding world
@Felthry how any treacle? I've heard people say that about treacle.
@starkatt Actually no, because I think we'd heard the word in a nursery rhyme or something
@starkatt that said, we didn't, and still don't, know what treacle is
if it's treacle tart, it's a kind of pie: https://en.wikipedia.org/wiki/Treacle_tart
things that come to mind immediately: christmas crackers, boarding schools having 'houses' with rivalries and stuff, houses having names instead of addresses