Common-sense reasoning is an interdisciplinary research area and cognitive concept that investigates the human ability to make inferences and predictions based on a vast, implicit store of everyday knowledge about the world, its objects, events, and social interactions. This knowledge is typically non-expert, incomplete, and often relies on heuristics, enabling flexible understanding and action in underspecified or novel situations. Its significance lies in facilitating robust, adaptive behavior in complex environments and represents a fundamental challenge in artificial intelligence for achieving human-level understanding and interaction.