Volume Element: A differential element used in integration to calculate volumes; in spherical coordinates, it is expressed as $dV = r^2 \sin(\theta) dr d\theta d\phi$.
Spherical Coordinates: A coordinate system where points are defined by their distance from the origin (radius), angle from the positive z-axis (polar angle), and angle from the positive x-axis in the xy-plane (azimuthal angle).
Gravitational Field: A vector field that represents the gravitational force per unit mass at each point in space.