In algebraic topology there is the cup product, which endows the direct sum of (singular) cohomology groups with the structure of an associative, graded-commutative, unital ring. Given an associative, unital ring $R$, there is also the Yoneda product between Ext groups of $R$-modules. If $R$ is commutative, then the direct sum of Ext groups $\bigoplus_{i=0}^{\infty}\operatorname{Ext}^i(M,M)$ becomes a graded ring, for any $R$-module $M$.
Sometimes the Yoneda product is called Yoneda cup product. Why is that? What is the connection between both notions?