Final answer:
Single Sign-On (SSO) is a type of system that allows a user to authenticate once to access multiple services.
Step-by-step explanation:
The type of system that allows a user to authenticate once to access multiple services is called Single Sign-On (SSO). SSO is a centralized authentication system that allows users to log in once, using a single set of credentials, and then access multiple applications and services without the need to reauthenticate.
Using SSO, a user can authenticate to a main identity provider, such as a directory service or a social media platform, and then be granted access to various services and applications that are integrated with the SSO system. This improves user experience by eliminating the need to remember and manage multiple usernames and passwords.
For example, a student can authenticate to their school's SSO system using their school email address and password, and then access their email, learning management system, and other school-related services without needing to login separately to each of them.