semilunar

Sem`i*lu"nar, a. Defn: Shaped like a half moon. Semilunar bone (Anat.), a bone of the carpus; the lunar. See Lunar, n. -- Semilunar, 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. Sem`i*lu"nar, n. (Anat.) Defn: The semilunar bone.

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