meniscus

plural meniscuses · plural menisci

1. A crescent moon, or an object shaped like it.First known use 17th c.

   And from Crabbe's own forehead sweat dripped or gathered into a kind of meniscus to be scooped off.

   1959, Anthony Burgess, Beds in the East (The Malayan Trilogy), published 1972, page 554

   1 more example

   He opened wide both casements; they gave on a parking place four floors below; the thin meniscus overhead was too wan to illumine the roofs of the houses descending toward the invisible lake [...].

   1972, Vladimir Nabokov, Transparent Things, McGraw-Hill, published 1972, page 19

2. engineeringA lens which is convex on one side and concave on the other, being crescent-shaped in cross-section.First known use 17th c.
3. The curved surface of liquids in tubes, whether concave or convex, caused by the surface tension of the liquid.First known use 19th c.
4. anatomyEither of two parts of the human knee that provide structural integrity to the knee when it undergoes tension and torsion.First known use 19th c.