Verb: The act of connecting to or accessing a computer system, network, server, or Web site. To login, you must provide a username and a password. For example, if you call your ISP's tech support, they may ask if you're currently logged in to the server; if you are not, they may ask you to try and log on.

Most personal computers have no log-on procedure

you just turn the machine on and begin working. For larger systems and networks, however, you usually need to enter a username and password before the computer system will allow you to execute programs.

(Also spelled as "log in", "log on", "logon".)

Noun: The account name (username) used to gain access to a computer system. Not a secret (contrast with Password).