## # Trees Introduction

- Tree data structure is a collection of Nodes (Data) which are organized in hierarchical structure

### # Terminologies

**Parent Node**- the node which has branch from it to any other node is called a parent node.**Child Node**- the node which is descendant of any node is called a child Node & all the nodes except A are child nodes.

**Root Node**- The first node of the tree is called the Root Node. It is the origin of tree data structure & in any tree, there is only one root node.**Leaf Node**- the node which does not have a child is called as Leaf Node & the leaf nodes are also called as External Nodes.**Internal Node**- the node which has at least one child is called an Internal Node.

**Degree**- the total number of children of a node is called as Degree of that Node &The highest degree of a node among all the nodes is called as Degree of Tree. i.e. 3

**Level**- In a tree each step from top to bottom is called as a Level & We start the levels from root node taking it as Level 0.

### Learn More

- Trees Introduction