semilunar bone n 1: one of the eight small wrist bones [syn: {lunate bone}, {semilunar bone}, {os lunatum}]
Semilunar \Sem`i*lu"nar\, a. Shaped like a half moon. [1913 Webster] {Semilunar bone} (Anat.), a bone of the carpus; the lunar. See {Lunar}, n. {Semilunar valves}, or {Sigmoid valves} (Anat.), the valves at the beginning of the aorta and of the pulmonary artery which prevent the blood from flowing back into the ventricle. [1913 Webster]