What is a leaf (leaf)?

A leaf is a tree node that has no children.

Characteristics:

• A leaf is an "end point" of the tree.
• It has no outgoing edges.
• Every path through the tree ends at a leaf.

Example:

Here D, E, and C are leaves, because there are no other nodes below them.

Properties:

• Every tree has at least one leaf.
• The number of leaves shows how "branched out" a tree is.

Summary: A leaf is a node where the downward path no longer continues, the final node of a tree.