1.NounA vector product."The cross product can be derived like so: given a pair of vectors
ξ
{\displaystyle \xi }
and
η
{\displaystyle \eta }
, solve for a vector
ζ
{\displaystyle \zeta }
which is perpendicular to both
ξ
{\displaystyle \xi }
and
η
{\displaystyle \eta }
, i.e., whose dot product with both
ξ
{\displaystyle \xi }
and
η
{\displaystyle \eta }
is zero."