Definition:Pairwise Disjoint/Family

Definition
An indexed family of sets $\left \langle {S_i} \right \rangle_{i \mathop \in I}$ is said to be pairwise disjoint :
 * $\forall i, j \in I: i \ne j \implies S_i \cap S_j = \varnothing$

Hence the indexed sets $S_i$ themselves, where $i \in I$, are referred to as being pairwise disjoint.

Also known as
Other names for pairwise disjoint include mutually disjoint and non-intersecting.