n. Mysterious woman who leaves a gigantic unflushable turd in the ladies' loo. Usually encountered in the workplace, sparking endless speculation about the identity of the Log Lady. No male equivalent, thanks to David Lynch, and the fact that men have such godawful personal hygiene that this is a pretty regular happening in the male crapper.
"The Log Lady struck again! Who d'you reckon it is?"
"That fat bird from the 4th floor!! She must have a tail-pipe six inches wide!"