What is the term for a connection point within a tree, also known as a vertex?

The term for a connection point within a tree structure, also known as a vertex, is "node." In the context of data structures, a node represents any element of the tree, which can hold data and link to other nodes. Each node can act as a point of connection, forming relationships with other nodes through edges, which are the connections between them.

The root is a special type of node that serves as the starting point of the tree, while leaves are nodes that do not have any children. Both the root and leaf nodes are specific instances of nodes within the more general category. Thus, when defining the basic units of a tree structure, it is accurate to refer to them collectively as nodes.