Definition:Pairwise Perpendicular

Definition
Let $S = \set {L_1, L_2, \ldots, L_n}$ be a set of lines in a Euclidean space.

Then the elements of $S$ are pairwise perpendicular
 * $\forall i, j \in \set {1, 2, \ldots, n}, i \ne j:$ $L_i$ and $L_j$ are perpendicular to each other.

Also known as
The term mutually perpendicular is also seen for pairwise perpendicular