The term 'signed on' can be described by four different crossword solutions: ENROLLED (8 letters), registered (10 letters), LOGGED (6 letters), and hired (5 letters). ENROLLED and registered both refer to the process of officially joining or becoming a part of something, such as an organization or school. Logging in usually refers to the process of entering a username and password to access a website or computer system. Hiring is the process of employing someone for a job. All four terms can be used to describe the act of signing on to something.