The term pairwise refers to taking all unordered 2-subsets of a given set. For example, the pairwise products of the set 
are 
, 
,
and 
.
Pairwise
See also
k, PairExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Pairwise." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Pairwise.html