Definition:Binary Tree
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Definition
A binary tree is a rooted tree which has at most two branches at any node.
That is, every node in a binary tree has degree of at most $3$ (one for the parent, two for the children).
The branches at any particular node are frequently called the left-hand branch and the right-hand branch, and a distinction is made between them.
Note
Binary trees are frequently used in computer science to store data in an efficiently search-able fashion.