Decision tree technical terms
Arc
Part of a branch connecting a parent node to a child node (subnode). In a decision tree, arcs are labelled to specify possible answers.
Branch
A path through the tree from the root node to any leaf node.
Node
A circle with a text label. Nodes represent decisions (leaf nodes) or questions (non-leaf nodes). The uppermost node in a tree is called the root node.
Parent node/child node
A pair of nodes that are directly connected (i.e. with no intervening nodes) on the same branch. Other family relationship terms have the obvious meanings, e.g. sibling nodes, descendant nodes, etc. Child nodes are sometimes called subnodes.
Subtree Part of a tree consisting of a node and all its descendant nodes.