I am italian too, and I probably understand what you mean.
Oxford dictionary:
Hollow
1 having a hole or empty space inside : each fiber has a hollow core.
• (of a thing) having a depression in its surface; concave : hollow cheeks.
From my point of view, I think that hollow is more about the shape of the object you are referring to. You should use empty instead to describe the content of a certain object.
For example, hydraulic tubes are hollow (it means that they are "cavitary" cylinders, ie a solid object with a cavity inside) and they could be empty (referred to the content of the "cavity")
Hope to be helpful
I think it's a very good explanation.
It's interesting that, while a tube and a
torus are
homeomorphic (unless we want to disregard the thickness of the tube's walls, it is just a stretched-out torus), we consider the tube to be hollow and not the torus. Both objects have a hole in the middle: if we put them both on the ground in such a way that the empty spaces can be seen from above, then horizontal cross-sections are of exactly the same kind for both -- they're
rings. However, for a torus to be hollow, this is not enough for some reason. It would need to have "hollow"
vertical cross-sections to be that.
I think it's because we don't really think of the hole in the middle of the torus to be
inside it.