%0 Journal Article %T On a generalization of $D3$-modules %A Diop, Papa Cheikhou %A Seye, Modou %A Maurya, Sanjeev Kumar %A Barry, Mamadou %J Indian Journal of Mathematics %V 67 %N 1 %D 2025 %P 109–132 %@ 0019-5324 %I The Allahabad Mathematical Society %K Small submodules, cosingular modules, projective modules, $D3$-modules, $D31$-modules. %X $ R $ is supposed to be an associative ring with identity and $ M $ be a unital left $R$-module. In this paper, we present the concept of a $D31$-module that generalizes the concept of a $D3$-module introduced in [14] and studied in [25] . A module $M$ is termed as $ D31 $-module if, whenever $ W $ and $ X $ are summands of $ M $ with $ W + X = M $ and $ W $ is cosingular, we have $ W \cap X $ is a direct summand of $ M $. We explore fundamental properties of these modules and establish that the class of rings $ R $ such that every $ D31 $-module is also a $ D3 $-module coincides precisely with the class of COSP-rings. Additionally, we examine the connections between $ D31 $-modules and other related module classes.