The term external direct product is used to refer to either the external direct sum of groups under the group operation of multiplication, or over infinitely many spaces in which the sum is not required to be finite. In the latter case, the operation is also called the Cartesian product.
External Direct Product
See also
Cartesian Product, External Direct SumExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "External Direct Product." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ExternalDirectProduct.html