Per Wikipedia, a (left) group action is defined as follows:
If $G $ is a group and $X$ is a set, then a (left) group action $φ$ of $G$ on $X$ is a function $$\varphi : G \times X \to X : (g,x)\mapsto \varphi(g,x)\cdots $$ (and so on).
My question is, what is the meaning of the "$\times$" notation in this context? It immediately calls to mind direct products and cross products. If so, it is defined via two groups, but $X$ here is a set than group, so I have my doubts.
It is the Cartesian product of (the underlying set of) $G$ with $X$, i.e., $$G\times X=\{(g, x)\mid g\in G, x\in X\}.$$