biconcavity
/ˌbaɪkɑnˈkævəti/
noun
- The quality or state of being curved inward on both sides, like a lens or a disk.
- The lens's biconcavity makes light rays spread out instead of focusing.
- The biconcavity of a red blood cell helps it carry oxygen efficiently.
- Scientists studied the biconcavity of the ancient coin to understand how it was minted.