I know I have met the following construction somewhere, but I cannot remember where. Let $A$ be a (unital associative) ring, and let $N$ be an $A$-$A$ bimodule. On the product set $A\times N$ we define multiplication by \begin{equation*} (a,m)(b,n) := (ab,\,an+mb)~. \end{equation*} The set $A\times N$ equipped with this multiplication is a (unital associative) ring with the two-sided ideal $0\times N$ whose product with itself is $0$. The ideal $0\times N$ is the kernel of the surjective homomorphism of rings $A\times N\to A : (a,n)\mapsto a$. If $A$ is Jacobson-semisimple, then $0\times N$ is the Jacobson radical of the ring $A\times N$.

Does this construction of the ring $A\times N$ from a ring $A$ and an $A$-$A$ bimodule $N$ have a name, and perhaps an established notation? The notation $A\times N$ is misleading since it suggests a direct product of rings, which it is not.