meniscus

/məˈnɪskəs/
noun
  1. A piece of cartilage in the knee joint that acts as a cushion and stabilizer.
    • The doctor explained that the meniscus helps distribute weight across the knee.
    • Surgery may be needed if the meniscus is badly damaged.
    • He tore his meniscus while playing basketball.
  2. The curved upper surface of a liquid in a tube, caused by surface tension.
    • The meniscus of water in a glass tube is concave, while mercury's meniscus is convex.
    • The lab technician carefully measured the liquid by aligning the meniscus with the mark.
    • To read the volume correctly, look at the bottom of the meniscus in the graduated cylinder.
  3. A lens that is convex on one side and concave on the other, shaped like a crescent.
    • A meniscus lens can focus light more precisely than a simple convex lens.
    • The camera's meniscus element helped produce sharper images.
    • The meniscus lens is used in some eyeglasses to reduce distortion.