Definitions
1.nounA crescent moon, or an object shaped like it.
2.nounA lens which is convex on one side and concave on the other, being crescent-shaped in cross-section.
3.nounThe curved surface of liquids in tubes, whether concave or convex, caused by the surface tension of the liquid.
4.nounEither of two parts of the human knee that provide structural integrity to the knee when it undergoes tension and torsion.