Dark data is the inactive or unused information stored away and overlooked,...

https://blogfreely.net/samuel-wang09/what-is-agentic-ai-and-why-does-dark-data-make-it-risky

Dark data is the inactive or unused information stored away and overlooked, making up about 60%-80% of most companies’ data. This hidden stash isn't just costing money—it creates risk and adds noise that can confuse AI projects