semilunar valve Syllabification: (sem·i·lu·nar valve)Definition of semilunar valve noun Anatomy each of a pair of valves in the heart, at the bases of the aorta and the pulmonary artery, consisting of three cusps or flaps that prevent the flow of blood back into the heart. semilunar valve in other Oxford dictionaries Definition of semilunar valve in the British & World English dictionary
