'Pittenweem' derives from the Pictish pit (place) and Gaelic na h-Uaimh (of the caves); meaning Place of the Caves. The cave in question is thought to be St Fillan's cave.
A story is told about an occasion when St Fillan was ploughing the fields near Killin. Fillan had put a spell had been put on the ox, so that, when a wolf killed it, the wolf had to take the place of the ox and do its work.