### Summary

A binary tree is a specific type of data structure where each node has at most two children, typically referred to as the left child and the right child. This structure is widely used in Machine Learning and AI for constructing decision trees and other tree-based models.

### ELI5

Imagine you’re playing a game of “20 questions”, where each question helps you get closer to guessing what someone is thinking about. A binary tree is like that game - it starts at a broad question (the root), and each answer leads to a narrower question (a branch). Each branch ends in the final answer or guess (leaves).

### In-depth explanation

In the field of Computer Science, a binary tree is a tree data structure where each node has at most two children, typically known as left child and right child. This tree model reflects hierarchical structure well and the tree concept is often used in explanations of structured programming, data management and computer networks.

The properties that define a binary tree make it useful for many algorithms. Two essential properties of binary trees are depth and balance. Depth is the length of the path from the root to the furthest leaf, while the balance is the difference between the least and most number of nodes compiled going from the root to any leaf.

In Artificial Intelligence, binary trees are particularly applicable when modelling decision processes. Each node of a binary tree could represent a decision, with the left and right child node representing the outcomes of that decision. A classical example of AI using binary trees are Decision Trees, which are machine learning algorithms that make a decision by learning simple decision rules inferred from training data.

Another example of binary trees in AI is in Search Algorithms, like the A* search algorithm often used for pathfinding and graph traversal. The binary tree structure aids the process by organizing the nodes in a way that optimizes searching efficiency.

Lastly, binary trees play a fundamental role in the implementation of Binary Heaps, a specific data type often used in designing efficient algorithms. Binary Heaps, and thus binary trees, are essential in efficient implementation of priority queue and thus helps in improving efficiency of Graph Algorithms and other similar usage.

Decision Trees, Tree Traversal, Search Algorithms, Binary Search Trees, Binary Heap, Graph Algorithms.