The Collaborative International Dictionary of English v.0.48:

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]

The Collaborative International Dictionary of English v.0.48:

Semilunar \Sem`i*lu"nar\, n. (Anat.)
   The semilunar bone.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lunar \Lu"nar\, n.
   1. (Astron.) A lunar distance.
      [1913 Webster]

   2. (Anat.) The middle bone of the proximal series of the
      carpus; -- called also semilunar, and intermedium.
      [1913 Webster]

WordNet (r) 3.0 (2006):

semilunar
    adj 1: resembling the new moon in shape [syn: crescent(a),
           crescent-shaped, semilunar, lunate]