parenta node in the tree with other connecting nodes is the parent of those nodes node is the parent of nodes deand childthis is node connected to its parent nodes and are children of node athe parent and root node siblingall nodes with the same parent are siblings this makes the nodes and siblings levelthe level of node is the number of connections from the root node the root node is at level nodes and are at level height of treethis is the number of levels in tree our tree has height of depththe depth of node is the number of edges from the root of the tree to that node the depth of node is we shall begin our treatment of trees by considering the node in tree and abstracting class tree nodes just as was the case with other data structures that we encounteredsuch as lists and stackstrees are built up of nodes but the nodes that make up tree need to contain data about the parent-child relationship that we mentioned earlier let us now look at how to build binary tree node class in pythonclass nodedef __init__(selfdata)self data data self right_child none self left_child none just like in our previous implementationsa node is container for data and holds references to other nodes being binary tree nodethese references are to the left and the right children to test this class outwe first create few nodesn node("root node" node("left child node" node("right child node" node("left grandchild node"