\begin{definition}[Definition:Scalar Multiplication/Module]
Let $\struct {G, +_G, \circ}_R$ be an module (either a left module or a right module or both), where:
:$\struct {R, +_R, \times_R}$ is a ring
:$\struct {G, +_G}$ is an abelian group.
The operation $\circ: R \times G \to G$ is called '''scalar multiplication'''.
\end{definition}