In the previous chapter, we introduced the concept of genuine multipartite entanglement (GME), presenting two algebraic methods for constructing a GME measure based on bipartite entanglements of a given quantum state. This chapter takes a different approach by proposing a geometric measure of GME with distinct advantages. Importantly, in our prior work [1], we employed squared concurrence (also known as the “two-tangle”) to construct geometric measures of genuine multipartite entanglement (GME). Building on new insights, we have since enhanced the effectiveness of our GME-measure framework by replacing squared concurrence with the square root of entanglement entropy. This chapter begins by introducing a new geometric measure of GME for a three-qubit pure system. Subsequently this measure is extended to a four-qubit pure system. We highlight a key advantage of these geometric measures: their ability to reveal the degree of permutation invariance among the quantum parties. Finally, these geometric measures are extended to mixed-state systems, broadening their applicability in real-world scenarios. We also discuss methods to evaluate and estimate mixed-state entanglement, both theoretically and experimentally.