A subtree of a tree T is a tree S consisting of a node in T and all of its descendants in T. The subtree corresponding to the root node is the entire tree; the subtree corresponding to any other node is called a proper subtree.

What is a subtree?

(definition) Definition: The tree which is a child of a node. Note: The name emphasizes that everything which is a descendant of a tree node is a tree, too, and is a subset of the larger tree.

Is binary a subtree?

A binary search tree is a rooted binary tree, whose internal nodes each store a key (and optionally, an associated value), and each has two distinguished sub-trees, commonly denoted left and right.