[phillord]

I wrote a different version of the pizza ontology years ago, where the level of "spiciness" was dependent on the country you came from -- so American "hot" was equivalent to British "Medium".

It's hard to do, ontologically, but you can. It tends to make your ontology very complex though, and at the same time incapable (because it's hard to detect contradictions). So you should only do it when you need to.