Is there a special name of an object that is basically a 3D annulus? I mean a case of a simple 2D annulus that is "elevated" straight from the ground up. A short tube/pipe could be an example of such object. In German it seems to be called "Hohlzylinder".
Here is what I mean:
A bonus question: I actually need to name only a part of this object that is defined by a central angle (like 90 degrees). How to name that? I am writing a thesis and don't know how to name this object.