Data loss prevention
Also known as DLP
Policies that detect sensitive data in transit and block, warn, or log when it moves somewhere it should not.
DLP inspects content for patterns like card numbers, medical record identifiers, or national insurance numbers, and applies an action when someone tries to email, upload, or copy it outside approved boundaries.
The practical difficulty is tuning. Rules that are too broad generate false positives until staff learn to click through every warning, at which point the control exists but no longer functions.
Where this comes up
Data loss prevention sits inside our microsoft 365 and cloud work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.