English: Universal charge density diagram of a continuous charge distribution - showing the volume charge density ρ, unit volume in the cube, surface charge density σ, unit normal to the surface n and unit surface denoted by the circle at the surface, dipole moment vector d, and the position vectors used in calculuations: the field point r, point in the distribution r', and relative positions between them. White arrows are vectors, black arrows are labels. For use with any context on charge distributions.