In the TCL, the term node is used to refer to an object in a tree structure which contains the stored_type element. The stored type element (element which you are storing in the tree) is not considered the node itself, but is contained within the node. The tree structure is, then made up of nodes, with the top node being the root node. All nodes in the tree structure have the same operations and properties of the tree itself.

Sometimes, the term element will be used to specify a node, especially when discussed with the STL, where all containers are said to contain elements. Although all TCL iterators iterate over nodes in the tree, the iterators actually expose the element which reside in the node. TCL iterators can also expose the node, with the use of the iterator's node() operation.