PEBKAC/peb'kak/ [Abbrev., "Problem Exists Between Keyboard And Chair"] Used by support people, particularly at call centers and help desks. Not used with the public. Denotes pilot error as the cause of the crash, especially stupid errors that even a luser could figure out. Very derogatory. Usage: "Did you ever figure out why that guy couldn't print?" "Yeah, he kept cancelling the operation before it could finish. PEBKAC."