part of
connected to
connecting branch of
b connecting-branch-of s iff b is connected to s, and there exists some tree-like structure t such that the mereological sum of b plus s is either the same as t or a branching-part-of t.
In the tree T depicted in https://oborel.github.io/obo-relations/branching_part_of.png, B1 is connecting branch of S, and B1-1 as a connecting branch of B1.
has connecting branch
in branching relationship with