Meniscus \Me*nis"cus\, n.; pl. L. Menisci (-s[=i]), E. Meniscuses. [NL., from Gr. ?, dim. of mh`nh the moon.]

1. A crescent.

2. (Opt.) A lens convex on one side and concave on the other.

3. (Anat.) An interarticular synovial cartilage or membrane; esp., one of the intervertebral synovial disks in some parts of the vertebral column of birds.

Converging meniscus, Diverging meniscus. See Lens.

Source: Webster's Revised Unabridged Dictionary (1913)