from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The process of identifying oneself to a computer, usually by entering one's username and password.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A combination of a user's identification and password used to enter a computer, program, network, etc.
- n. The process of logging in.
From the verb log in. (Wiktionary)