An orthogonal coordinate system is a system of curvilinear coordinates in which each family of surfaces intersects the others at right angles. Orthogonal coordinates therefore satisfy the additional constraint that (u_i)^^·(u_j)^^ = δ_(i j), where δ_(i j) is the Kronecker delta.

change of variables theorem | curl | curvilinear coordinates | cyclidic coordinates | divergence | gradient | Jacobian | Laplacian | skew coordinate system