Definition:Orthogonal Curvilinear Coordinates

Definition
Let $\KK$ be a curvilinear coordinate system in $3$-space.

Let $\QQ_1$, $\QQ_2$ and $\QQ_3$ denote the one-parameter families that define the curvilinear coordinates.

Also see

 * Equivalence of Definitions of Orthogonal Curvilinear Coordinates