Microsoft Purview policies that detect sensitive information and apply actions, such as blocking sharing, showing policy tips, or generating alerts. They protect Exchange, SharePoint, OneDrive, Teams, devices (Endpoint DLP), and more.
In SC-900: preventing card numbers from being emailed to external recipients → DLP; preventing sensitive files from being copied to USB → Endpoint DLP. Don't confuse it with retention, which controls how long content is kept.
Data loss prevention (DLP) is a concept that can show up on the exam. Check the full guide to see it in context.