Definition of Meniscus

Noun: meniscus (menisci,meniscuses) mi'nis-kus

(anatomy) a disk of cartilage that serves as a cushion between the ends of bones that meet at a joint
- semilunar cartilage
(optics) a lens that is concave on one side and convex on the other
(physics) the curved upper surface of a nonturbulent liquid in a vertical tube