Leaf of a rooted tree
= Leaf of a rooted tree
= Leaves of a rooted tree
{synonym}
A node with no <children in a rooted tree>. This depends on the chosen root: the root of a nontrivial <tree> can have undirected <vertex degree> one while still having a child and therefore not being a leaf in the rooted sense. In a single-node <rooted tree>, the root is a leaf. The distinction matters when counting the complement of the <internal vertices of a rooted tree>.