What Does Active Directory Federated Services (ADFS) Mean?
Active Directory Federated Services (ADFS) is software designed by Microsoft for the Windows operating system that provides users with a single sign-in for all access points and applications throughout the organization. It follows a claim-based access that allows the user full access with a single sign-in while maintaining security and federated identity.
Techopedia Explains Active Directory Federated Services (ADFS)
In ADFS, an identity federation is constructed between two organizations. On one side is the federation server, which authenticates the user through standard accepted means using an active directory and issues tokens containing the user's claims. On the other side is the resources. Federation services validates this token and accepts the claimed identity. This allows the federation to provide a user with access to resources that essentially belong to another secure server.
Basically, if a user logs in to his personal computer at work, the user does not require a separate login; he automatically is logged in using ADFS. He can now access information in the logged-in stage through his work computer.