Before we walk through how the tree data structure can be utilized to manage data, there are some key terminologies you should become familiar with. This guide walks through each of these terms. You can use this guide as reference/cheat sheet for the tree data structure terminology.

## Root

**Definition:** The very top node of a tree.

## Child

**Definition:** Any node connected to another node, while moving away from the root node.

## Parent

**Definition:** A node that contains child nodes

## Siblings

**Definition:** Multiple nodes connected to the same parent node.

## Leaf

**Definition:** A node with no child nodes.

## Edge

**Definition:** Connection between one node to another node.

## Path

**Definition:** A sequence of nodes connecting a node with a descendant node.

## Tree Height

**Definition:** Number of edges in the longest path from the root to the leaf node.

## Depth

**Definition:** Number of edges from a node to the tree’s root node.

## Summary

Now that you have a good idea of the key terms associated with trees you’re ready to start walking through each of the key structures and how they can be used.