U+222C "∬" Double Integral Unicode Character

U+222C "∬" Double Integral is a mathematical symbol used to denote the integration of a function over a two-dimensional region, such as a surface or area. It represents the application of two successive single integral operations, commonly employed in calculus, physics, and engineering contexts to compute quantities like flux, volume under a surface, or surface integrals across a given plane. Unlike a single integral symbol, the double integral indicates that the integration is performed with respect to two variables, often visualized as summing infinitesimal elements across a 2D domain.