sourdough
adjective
°Describing something made from dough that was leavened with yeast that produce acids giving a sour taste.
noun
°Dough, leavened with yeast that produce acids giving a sour taste.
°(slang) An old-timer, especially in Alaska. From the distinctive pouches of bread starter worn on a belt or around the neck by experienced prospectors during the Klondike Gold Rush.