[from the pioneering Roundtable chat system in Houston ca. 1984; prob. originated as a typo for 'scroll']
n. The log of old messages, available for later perusal or to help one get back in synch with the conversation. It was originally called the 'scrool monster', because an early version of the roundtable software had a bug where it would dump all 8K of scrool on a user's terminal.