A node stores a value. All smaller values are in the left subtree. All larger values are in the right subtree. The left and right subtrees are also heaps. The tree is nearly-complete.
Trees are good for hierarchical structures, like advising relationships in graduate school.
A Tree ADT Purposefully left open. I'm going to ask you to design this one. Filled in some details. These are based primarily on outline 45 of CSC152 99S . Updated to better represent what happened.