Tree

A diagram of lines connecting "nodes", with paths that go outwards and do not loop back.

It has many uses, such as factor trees (on the right) and probability trees (below).

They look a little like an upside down tree (or a tree on its side) don't they?

• The starting node is called the "root".
• Each following node is a "child" (and the one it came from is its "parent").
• A node without children is called a "leaf".