TERM:
Federated identity

Definition:

A federated identity is the means of linking a person’s electronic identity and attributes stored across multiple distinct identity management systems. Without federated identity, users are forced to manage different credentials for every site they use.

Related to federated identity is single sign-on (SSO), in which a user’s single authentication ticket, or token, is trusted across multiple IT systems or even organizations. SSO is a subset of federated identity management, as it relates only to authentication and is understood on the level of technical interoperability which would not be possible without some sort of federation.