  An entanglement bound based on local measurements is introduced for
multipartite pure states. It is the upper bound of the geometric measure and
the relative entropy of entanglement. It is the lower bound of minimal
measurement entropy. For pure bipartite states, the bound is equal to the
entanglement entropy. The bound is applied to pure tripartite qubit states and
the exact tripartite relative entropy of entanglement is obtained for a wide
class of states.
