A binary tree is a data structure in computer science where each node has at most two children, referred to as the left child and the right child. This structure allows for efficient data organization and retrieval, making it useful in various applications such as searching and sorting algorithms. In a binary tree, the top node is called the root, and each child node can further have its own children, forming a hierarchical structure. Common types of binary trees include binary search trees and balanced trees, which help maintain order and improve performance in operations like insertion, deletion, and traversal.