If they can be accessed from anywhere in your code ( inside or outside functions ) then they are Global by definition.
So a function is a global ...
Your definition come with variable.
Types are other kind of variables, but more like any entity or image/textures etc... in Blitz3D; you need variable to point to them.. so we can't really compare types to variables.
You have to think about they are not variables, and there, you'll can imagine "Why" they are so special ^^ ... sometimes local, sometimes global... sometimes both, and sometines any -_-' ... types are not globals .