Personally Identifiable Information (PII) is any information that can be used to identify a specific individual. This includes name, address, phone number, date of birth and even social security number.
PII does not include all personal information about an individual. For example, a person's name and age are generally considered PII but the fact that they like chocolate ice cream is not PII because it does not identify a specific person. In addition, PII is often combined with other types of information to create personally identifiable profiles of individuals.
The term "personally identifiable information" was first used in 1989 by the U.S. Department of Health and Human Services to describe sensitive health data that could be used to identify an individual person.
The definition has been expanded since then to include personally identifiable financial information such as credit card numbers, bank account numbers and social security numbers as well as other types of personal data such as biometric identifiers like fingerprints or retinal scans.