Personally Identifiable Information (PII) refers to any data that can be used to identify a specific individual, either directly or indirectly. Examples include full name, Social Security number, date of birth, address, email address, phone number, and biometric identifiers.

PII is regulated by numerous laws and standards, including privacy regulations and data protection frameworks. Protecting PII is critical to prevent identity theft, fraud, and privacy violations.

Health information is a subset of sensitive data (often classified as PHI). Trade secrets and business data fall under intellectual property. Information classification levels describe value, not identity.

Security controls for PII typically include encryption, access control, monitoring, and data loss prevention mechanisms.