terminology let' consider some terms associated with trees to understand treeswe need to first understand the basic ideas on which they rest the following figure contains typical tree consisting of character nodes lettered through to here is list of terms associated with treenodeeach circled alphabet represents node node is any structure that holds data root nodethe root node is the only node from which all other nodes come tree with an undistinguishable root node cannot be considered as tree the root node in our tree is the node sub-treea sub-tree of tree is tree with its nodes being descendant of some other tree nodes fkand form sub-tree of the original tree consisting of all the nodes degreethe number of sub-trees of given node tree consisting of only one node has degree of this one tree node is also considered as tree by all standards the degree of node is leaf nodethis is node with degree of nodes jeklhmand are all leaf nodes edgethe connection between two nodes an edge can sometimes connect node to itselfmaking the edge appear as loop