PII

Personally identifiable information — any data that identifies a person on its own (a name, an email, an IP address, a device fingerprint) or in combination with other data; the thing every privacy law is about

GDPR's term is "personal data" and it is broader than the US intuition — an IP address and a hashed identifier both qualify. The practical test is not "does this field say who" but "could this field, joined with what else we hold, say who". The membership store holds addresses; the analytics holds none, on purpose.