A
tree is a hierarchical
data structure made up of
nodes. Each node has zero or more
child nodes, which are below it in the tree (in
computer science, unlike in nature trees grow down, not up). In some trees, nodes also have a link to the node above them, which is called their
parent node. The base node of the tree is called the
root node. Nodes with no children are called
leaf nodes.
See binary search tree, heap