Binary search trees are node-based binary trees where each node contains a key and value. Each internal node has between 1 and 2 children, while leaf nodes have no children. The root node is the highest node with no parent. Traversal of a binary search tree involves systematically visiting each node and can be done in pre-order, in-order, or post-order fashion where the order of visiting left/right subtrees and the root node differs for each.