x1 (node in a tree graph) and x2 (node in the same tree graph) have an essentially-unique most recent (graph-nearest) common ancestor node A such that x3 [nonnegative integer; li] is d(A, x1) and such that x4 [nonnegative integer; li] is d(A, x2), where d is the graph geodesic distance (defined to be infinite if nodes are not connected in the correct direction).
This word is much like "tseingu" except the focus is on the relationships between x1 and x2 each with their mutual most recent common ancestor; notice that this word is pretty natural, whereas "tseingu" is not (and is probably malgli except for the purpose of translations). For nodes x1 and x2 in a tree, (x3,x is named by Curtis Franks to be the "ancestance between x1 and x2 (in that order)". In order to preserve meaning, mutual exchange of x1 and/with x2 must necessitate or be necessitated by mutual exchange of x3 and/with x4.