A node, also sometimes called a vertex, is a singular element of a graph that will generally but optionally contain the following
- Data
- A pointer to one or multiple other nodes
In the case of a tree, the nodes that a node points to are generally called children. The maximum amount of children a node can have generally decides on the r-arity of a tree, I.e, whether a tree is unary, binary, or tri-ary etc.