single sign-on

Single sign-on (SSO) is the practice of offering users access to all of their password-protected applications by inputing only one master password. This lets users unlock other systems and accounts secured by different passwords by doing only one authetication check. This is a meaningful aspect of reducing password fatigue brought on by having to type in one's username and password regularly
whenever access to a system or an account is necessary.  This is mostly accomplsihed using the LIghtweight Directory Access Protocol(LDAP) and related LDAp databases on directory servers. By having only one authenticating system, it's possible for all the services and acconts to be inherited by only one password, while all known passwords and usernames from the man operating the system are stored.