An Etymological Dictionary of Astronomy and Astrophysics

1. In → graph theory, a → rooted tree that has a natural orientation in which all → paths are directed away from the → root. More specifically, a → directed graph in which, for a → vertex u, called the → root, and any other vertex v, there is exactly one → directed path from u to v.
   

   2. Biology: The state of being branched, or treelike, in structure, appearance, growth, or other properties.

Etymology (EN): From Fr. arborescence, from → arborescent + → -ance.

Etymology (PE): Šâkedâri, nous from šâkedâr, → arborescent.