IPA: //ˌbaɪ.kɒnˈkæv.ɪ.ti//
KK: /baɪˈkɒnˌkævɪti/
The state of having two curved surfaces that are both concave, resembling the shape of a biconcave lens or certain types of cells.
The biconcavity of the lens allows it to focus light more effectively.
Biconcavity → It is formed from "bi-" (meaning two) and "concavus" (from Latin, meaning hollow or curved inward) and "-ity" (meaning the state or condition of). The word describes the state of having two hollow or inward curves.
Think of 'two' ('bi-') inward curves ('concavus') to remember that 'biconcavity' refers to a shape that has two concave surfaces.