Personal data breach

Definition in the Law art. 4

a breach of security leading to the accidental or unlawful destruction, loss, alteration or unauthorised disclosure of, or access to, personal data transmitted, stored or otherwise processed;

In plain words

A personal data breach is a breach of security that leads, accidentally or unlawfully, to the destruction, loss, alteration or unauthorised disclosure of, or access to, personal data. Losing an unencrypted laptop that holds customer data, or sending an email to the wrong person by mistake, can be such a breach.