| actor | Actor | ActivityPub, FOAF, Cedar, proposal | Participation root. ActivityPub actor is server-hosted; FOAF Agent includes persons. |
| natural person | Natural Person | FOAF, Schema.org, NIST, GDPR | Human being; FOAF Person and Schema.org Person align strongly. |
| user | Convenience label only | SCIM, LDAP, Keycloak, ZITADEL, apps | Overloaded. Map by context: SCIM/LDAP User → Identity Record; Keycloak/ZITADEL User → Account. |
| account | Account | SCIM, LDAP posixAccount, FOAF OnlineAccount, Keycloak | Operational access record in a scope. FOAF separates account from person explicitly. |
| identity | Identity Record or Claim | Kratos, OIDC, DID, VC, apps | Kratos Identity = traits + credentials. Avoid bare `identity` as root noun. |
| identifier | Identifier | OIDC sub, SAML NameID, LDAP DN, DID, WebID | Value referring within or across scopes. See Scoped Identifier when correlation is limited. |
| scoped identifier | Scoped Identifier | OIDC pairwise, SAML transient, pseudonyms | Meaning limited to RP, sector, tenant, or session. |
| persona | Persona | proposal, privacy patterns | Contextual presentation; pairwise/pseudonymous profiles map here. |
| agent | Actor or Artificial Agent | FOAF, ActivityPub, WebID | FOAF Agent includes humans; ActivityPub Service = Artificial Agent. |
| bot | Artificial Agent | ActivityPub Service, apps | Automated actor; may use Service Account. |
| service account | Service Account | Keycloak, ZITADEL machine user, Kratos | Non-human login or API identity. ZITADEL machine user, Kratos service patterns. |
| machine user | Service Account | ZITADEL | Product term for non-human org identity. |
| organization | Organization | Schema.org, Keycloak Orgs, ZITADEL, SCIM ext | Collective actor. SCIM `organization` attribute is not an Organization actor. |
| legal entity | Legal Entity | business, compliance | Organization recognized under law; separate from tenant. |
| community | Community | ActivityPub Group, proposal | Participation-oriented collective. ActivityPub Group may be Community or Group. |
| family | Family or Household | proposal, GDPR-sensitive | Guardian/dependent semantics; privacy-sensitive. |
| household | Family or Household | family accounts | Co-residence unit; may differ from legal family. |
| group | Group | LDAP, SCIM, FOAF, ActivityPub, Cedar | Named collection. LDAP/SCIM group ≠ social community without context. |
| team | Group or Organization Unit | Schema.org, collaboration | Collaboration unit; may be org sub-unit. |
| role | Role | Keycloak, ZITADEL, Cedar, Cerbos, Schema.org OrganizationRole | Capability bundle or relationship label. Cerbos derived role may hide Ownership. |
| grant | Role assignment | ZITADEL | Project role assignment; map to Delegation-like relationship. |
| member | Membership Relationship | SCIM, LDAP, FOAF, Schema.org, Zanzibar | Relationship edge, not a noun for the participant. |
| affiliation | Affiliation Relationship | Schema.org, FOAF knows | Looser than membership. FOAF knows is weak social affiliation. |
| follower | Following Relationship | ActivityPub | Directed social subscription; not membership or authz. |