A way of traversing a tree that processes the current node after processing the left and right subtrees. This is a depth-first algorithm, and can be compared to preorder traversal and inorder traversal.

Preorder Traversal | Postorder Traversal | Inorder Traversal

1. Traverse the left subtree.
2. Traverse the right subtree.
3. Visit the root.

For those of us who are visual learners, the postorder traversal of a binary tree would look like this.

           F     depth = 0
          / \
         B   E   depth = 1
        /   / \
       A   C   D depth = 2