Single Sign-On (SSO) is an authentication process that allows a user to access multiple applications or systems with one set of login credentials. This process centralizes the authentication mechanism, simplifying the user experience by eliminating the need for multiple usernames and passwords. SSO works by authenticating the user for all the applications they have been granted rights to and eliminating further prompts when they switch applications during a particular session. It's commonly used in enterprise environments to streamline the management of various applications and services and improve security by reducing the likelihood of password fatigue and reuse. Additionally, it provides ease of use for users, as they need to remember only one set of credentials.