Binary Tree: A recursive structure
A binary tree is a recursive structure. You can imagine there is a left and a right subtree to the sides of the root, each with their own root and left/right subtrees, each with their own root and $\dots$
In a tree $T$, a node $n$ together with all of its descendants, if any, is called a subtree of $T$. Node $n$ is the root of this subtree.
The recursive structure of tree lends itself to recursive implementation of operations on it.
Resources
- Definition on Dictionary of Algorithms and Data Structures: recursive data structure.