Federation allows a user to associate two accounts with each other. This allows the user to log in to one account and access the resources of the other account without logging in to the second account. It is one method for providing single sign-on when a user has accounts in multiple user stores.
Section 4.2.3, Configuring User Identification Methods for Federation
Section 4.2.10, Understanding How Access Manager Uses OAuth and OpenID Connect
Section 4.2.11, Configuring Authentication Through Federation for Specific Providers
Section 4.2.12, Integrating Amazon Web Services with Access Manager
Section 4.2.13, Configuring Single Sign-On for Office 365 Services