Trees are data structures that are used to represent sets of linked nodes arranged in a hierarchical form. A tree is a connected graph with no cycles. The tree is a connected acyclic graph. A tree is a set of straight line segments connected at their ends containing no closed loops. A tree is a connected acyclic graph i.e. a tree has no cyclic paths. A tree is a set of elements or nodes, such that each element is connected to at least one other element, and where the sequence of connections between any two elements is unique. A tree can be uniquely represented by specifying the parent node for every node and there exists a root in nodes such that the root has no parent and is unique. A tree has no cyclic paths.