\Sem`i*lu"nar\, a.
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.)
The semilunar bone.