Definitions

Tree: T

A connected graph, without any cycles, made of nodes with one being a root. Tree has a shortest path between two arbitrary nodes.

Node

A vertex in a graph

Root

The starting node, usually at the top of the tree

Parent Node

A node that exists a level above an arbitrary node

Child Node

A node that exists a level below an arbitrary node

Sibling Node

A node that has a same parent node as that of an arbitrary node

Leaf Node

A node that has no child node

Interior Node

A node that is neither a root node nor a leaf node

Ancestor Node

All nodes that are included in the path from the root node to an arbitrary node

Descendant Node

All nodes that are included in the path from an arbitrary node to a leaf node

Degree

Number of child nodes an arbitrary node has

Binary Tree

A tree with max degree of 2

Complete Binary Tree

A binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible

Full Binary Tree

A tree in which every node other than the leaves has two children

Skewed Binary Tree

A type of binary tree in which all the nodes have only either one child or no child