menisci

noun pl. meniscuses or menisci

1. a crescent or crescent-shaped thing
2. a lens convex on one side and concave on the other
3. fibrous cartilage within a joint, esp. of the knee
4. Physics the curved upper surface of a column of liquid: as a result of capillarity it is concave when the walls of the container strongly attract the liquid, as is the case with water, and it is convex when the liquid is more strongly attracted to itself, as is the case with mercury