x1 is a tube/hole/tunnel through (topological) torus x2.
In mathematics, this really does not have meaningful content. The region is the exterior space to the torus, which is between/within the longitudinal diameter of the in-circle by projection or possibly between/within the diameter of the inner circle by projection, should there exist any exterior at all. The meaning of "torus" is extremely general (it could be of any genus, it could be toroidal by any standard (although topology is probable), etc.). This word is extremely useful in normal converation in that it is one of the common meanings of "hole" or "tunnel", although it does not emphasize material, origin or destination, or that passage is even possible; poking a hole through something or carving a tunnel through it produce holes of this sense. A handle on a coffee cup encloses this space; the well where coffee goes is not a hole in this sense (see "sra'akpa"). See also: tubnu, kevna, greke'a.