Answer
The cardinal number is a product...
Work Step by Step
The Cartesian product of two sets, $A$ and $B$,
The set of all ordered pairs $(a,b)$ with $a\in A$ and $b\in B$:
A$\times B=\{(a, b)|a\in$A and $b\in B\}$
The cardinal number of such a set is $\mathrm{n}(\mathrm{A})\cdot n(B) $
( a product ) giving the idea the idea for Cartesian PRODUCT .
(Also, "Cartesian" is in the honor of Rene Descartes, a pioneer in algebraic (analytical) geometry)
