An area vector is a vector that represents both the magnitude and the orientation of a surface area. Its magnitude is equal to the area, and its direction is perpendicular (normal) to the surface.
Electric Flux: The measure of the electric field passing through a given surface, calculated as $\Phi_E = \mathbf{E} \cdot \mathbf{A}$ where $\mathbf{A}$ is the area vector.
Gauss's Law: A fundamental law stating that the total electric flux through any closed surface is equal to $\frac{Q_{enc}}{\epsilon_0}$, where $Q_{enc}$ is the enclosed charge.
Surface Integral: An integral used to calculate quantities over a surface by summing contributions from infinitesimal elements represented by their respective area vectors.